Cavitation

14th European Sonochemistry Society meeting

2012-11-11T12:00:00.002-08:00

14th European Sonochemistry Society meeting (ESS 14) will be held at Avignon, France during July, 2014.

The details about this conference will be updated in the future.

1st Meeting of the Asia-Oceania Society of Sonochemistry

2012-11-11T11:58:00.002-08:00

Conference website
http://sono.chemistry.unimelb.edu.au/aoss/

1st Meeting of the Asia-Oceania Society of Sonochemistry will be held at University of Melbourne, Australia during July 10-12, 2013.

Important dates :
Abstract submission dateline: Feb 28, 2013
Acceptance notification: March 31, 2013

The organizing committee of the society invites international sonochemists to the
first meeting of the Asia-Oceanic Society of Sonochemistry to be held in The
University of Melbourne, Melbourne Australia during July 10-12, 2013. The
meeting aims to provide a platform for academic presentations and discussions on
the following fields:
• Cavitation, Sonochemistry & Sonoluminescence
• Sonoprocessing (e.g.: Dairy, Food, etc.)
• Materials Science (e.g.: Colloids and Nanomaterials, etc.)
• Environmental Sonochemistry
• Ultrasound in Medical Applications
• Other Related Areas
The program will include plenary lectures, oral
as well as poster presentations.

A bubble journal: Bubble Science, Engineering & Technology

2012-10-18T13:39:00.002-07:00

Bubble Science, Engineering & Technology
ISSN 1758-8960, Online ISSN: 1758-8979
Publisher: Maney publishing
Established in 2008
2 issues per year
Journal website
http://www.ingentaconnect.com/content/maney/bub

Editor:
Professor Mohan J Edirisinghe (University College London, UK)

Co-editor:
Professor Carlos Martinez (Purdue University, USA)

Introduction of Journal (directly adapted from their website)
Bubble Science, Engineering and Technology is a unique multidisciplinary resource which publishes high quality innovative research on the generation, properties and applications of bubbles in the life and physical sciences, engineering and medicine.

There is rapidly growing interest in the production and control of bubbles in numerous disciplines. Suspensions of stable gas microbubbles play a vital role in the food, cosmetics and pharmaceutical industries, as well as in biotechnology, environmental engineering, and minerals and materials processing. In molecular biology, microbubbles are central to the mesoscale self-assembly of smart materials, microfabrication and DNA-driven assembly. Microbubbles have also shown great promise in therapeutic applications such as targeted drug delivery, gene therapy, thrombolysis and ultrasound surgery, and are the most effective type of contrast agent available for ultrasound radiography.

Recent developments in processing, diagnostics and therapeutics have generated a greatly increased need for advanced preparation technologies that provide a high degree of control over microbubble characteristics. Achieving these objectives requires multidisciplinary collaboration and Bubble Science, Engineering and Technology provides an effective resource for researchers in bubbles research to facilitate these interactions.

A list of conferences on cavitation and bubble dynamics

2012-05-25T08:48:00.001-07:00

This list will be updated. The conference is ordered by their date.

2014

14th European Sonochemistry Society meeting (ESS 14) (July, 2014, Avignon, France)

2013

1st Meeting of the Asia-Oceania Society of Sonochemistry (July 10-12, 2013, University of Melbourne, Australia)

2013 International conference on multiphase flow (May, 2013, Jeju Island, South Korea)

2012

8th International Symposium on Heat Transfer (Oct 21-24, 2012, Tsinghua University, China)

13th Modern Mathmatics and Mechanics (Oct 6-8, 2012, Shanghai, China)

26th IAHR Symposium on Hydraulic Machinery and Systems (August 19-23, 2012, Tsinghua University, Beijing, China)

10th International conference on hydrodynamics (Oct 1-4, 2012, Saint-Petersburg, Russia)

8th international symposium on cavitation (13th - 16th August 2012, Sinapore)

10th International conference on hydrodynamics (Oct 1-4, 2012, Saint-Petersburg, Russia)

2012-05-25T08:41:00.002-07:00

http://www.ichd2012.org/

The Conference is held by Krylov Shipbuilding Research Institute (KSRI) – one of the major Shipbuilding and Hydrodynamic research centers in the world.

Important dates

Receipt of abstracts 1st of March, 2012
Notification of provisional acceptance 25 of March, 2012
Receipt of full length paper 20th of May, 2012
Notification of final acceptance 1st of June, 2012
Early registration 20th of May, 2012

Bubbles in micro- or zero- gravity

2012-05-25T08:15:00.000-07:00

Bubbles in micro- or zero- gravity show some striking behaviors. Such experiments are often conducted on the International Space Station or parabolic flights.

During April, 2012, Don Pettit, a NASA astronaut, conducted an experiment by injecting bubbles into bubbles on the International Space Station. Without gravity, the rim between bubbles becomes very thick and can also last for a long time. Don Pettit also used laser to reflect different layers of bubbles.

Bubble experiment made by Don Pettit on the International Space Station. From Youtube. Also reported by DailyMail.

The bubbles made by Don Pettit are usually referred as antibubble, which is is a thin film of air surrounding liquid.

A schematic show of antibubble. Source

In 2010, Japanese astronaut Naoko Yamazaki mixed red tropical fruit juice with soap and blew shiny red bubbles. Because of zero-gravity environment, color pigments can spread evenly around a bubble in space. But on the earth, due to the gravity, the bubble will be colorless with the same recipe.

Bubble on the earth (left) and on the space (right). Source Also refer to Link.

"Flash&Splash" team, officially affiliated with the Cavitation Research Group at EPFL (École Polytechnique Fédérale de Lausanne, Switzerland), has conducted a series of experiments of fundamental research on bubbles on the parabolic flights. Water drops with centimetric diameters were produced by the micro-gravity platform (Obreschkow et al., 2008, p.15). An electrode was used to generate cavitation bubbles. The shock wave propagation in this confined water drops was visualized and studied. Bubble collapse under variable gravity was also compared.

Parabolic flights by Airbus A300 zero-g managed by European Space Agency (ESA). From Flash & Splash. Link Also refer to Obreschkow et al. (2008, Fig.1a).

Cavitation bubbles inside water drops in microgravity. Obreschkow et al. (2007). Download link

Cavitation bubbles in variable gravity. From EPFL webiste Link. Also refer to Obreschkow et al. (2011).

Based on the data of bubble sonoluminescence collected on parabolic research aircraft of NASA, Tom Matula (Applied Physical Laboratory, University of Washington, USA) concluded that the sonoluminescence intensity increases in microgravity.

References

Matula, T.J. (2000). Single-bubble sonoluminescence in microgravity, Ultrasonics, Volume 38, Issues 1–8, March 2000, Pages 559–565.

Obreschkow, D. et al. (2011). Universal Scaling Law for Jets of Collapsing Bubbles, PRL 107, 204501 (2011). pdf

Obreschkow, D. et al. (2008). Microgravity experiment: The fate of confined shockwaves, Proceedings o WIMRC cavitation forum 2008, July,7-9, Coventry, UK, pp.15-19.

Obreschkow, D. et al. (2007). Cavitation bubbles inside water drops in microgravity, APS DFD Movie contest.

Supersonic phenomenon in the kitchen

2012-05-25T02:28:00.001-07:00

According to a recent study (Gekle, et al., 2010), one can make a supersonic air jet flow by just dropping a solid object into water in the kitchen. The "jet" to scientists usually refers to a high-speed flowing column of material (e.g. air or water). The jet is quite common in daily life e.g. water out of a hose for cleaning. The aircraft is usually pushed forward by a supersonic air flow out from the back of engine, termed turbo-jet.

When we drop a heavy solid object into a liquid (e.g. a marble into a bowl of water), three jets will be generated during the process (Lathrop, 2010): one of upward supersonic air jet, an upward water jet and a downward water jet toward the object (e.g. marble in this case). When the air escaping through the "neck" formed during this process, it can be greatly accelerated even to supersonic flow by the pressure difference between the collapsing cavity and outer space (Gekle, et al., 2010).

The impact of a heavy object on a fluid surface causes a sequence of events leading to the creation of three jets. From Lathrop (2010). Link

In Gekle, et al. (2010), a carefully controlled disk is used. The disk is pushed into the water with certain speed and the whole process was recorded using high-speed camera. The physical process is similar like those described above. Fine smoke particles were used to measure the speed of the air flow. Disk with different shapes were also used to study the collapse of non-symmetric cavities (Enriquez et al., 2010).

Supersonic air flow. From Gekle et al. (2010, Fig.1).

Collapse of non-symmetric cavities. From Enriquez et al. (2010). Link

Recorded sequences from the top of disk during collapse of non-symmetric cavities. From Enriquez et al. (2010). More information is available on the website of Physics of Fluids Group, University of Twente, Netherlands. Link

You can try it in your own kitchen!

References
J. Eggers and E. Villermaux, Rep. Prog. Phys. 71, 036601 (2008).
Enriquez, O.R. et al. (2010). Collapse of nonaxisymmetric cavities, Phys. Fluids 22, 091104. Link

D. P. Lathrop, Making a supersonic jet in your kitchen, Physics 3, 4 (2010). Link

S. Gekle, I. R. Peters, J. M. Gordillo, D. van der Meer, and D. Lohse, Phys. Rev. Lett. 104, 024501 (2010).

S. Gekle, J. M. Gordillo, D. van der Meer, and D. Lohse, Phys. Rev. Lett. 102, 034502 (2009).

A list of articles about amazing bubble world

2012-05-23T10:10:00.000-07:00

Here, a list of articles published on this blog are given, sorted and updated for reader's convenience.

Fundamentals

Classifications of cavitation
Rectified diffusion
Bubbles in micro- or zero- gravity
Antibubbles
Sonochemistry
Sonoluminescence
Bubble collapse near boundaries
Bubble dynamics in da Vinci’s manuscript: Leonardo's paradox

Daily life

Supersonic phenomenon in the kitchen
Soap bubbles

Technologies

Cavitation-effect lithotripsy
The use of ultrasonic cavitation for kidney stone crush
Ultrasound contrast agent
Magnetic bubbles
Ultrasonic degassing in molten alloys
Cavitation in fluid machinery
Super-cavitation

Marine life

Dolphins and bubbles
Cavitation induced by snapping shrimp
Humpback whale's bubble net
Whales' stranding: the role of bubbles

Others

Write with bubbles
Bubbles in galleries and poems

Cavitation-effect lithotripsy

2012-05-23T09:42:00.000-07:00

Chinese version

Extracorporeal shock wave lithotripsy (SWL) is a currently widely used non-invasive treatment of kidney-, gall- and bladder- stones, using thousands of focused shock waves generated outside body to smash stones into small fragments which can naturally pass through the urethra. The shock wave source with a water-filled coupling cushion contacts the body directly. This technique was initially developed in 1980 by Dornier Medizintechnik GmbH (now Dornier MedTech Systems GmbH), Germany and has been widely spread since the introduction of the first commercial lithotriptor Dornier HM3 in 1983. There are many mechanisms for the stone fragmentation during SWL, e.g. direct stress, cavitation and fatigue. In this article, only cavitation effect during lithotripsy is briefly introduced. The drawbacks of SWL are also discussed and some alternative techniques for stone crush are introduced.

Numerous studies have confirmed the cavitation effect during lithotripsy. Generally speaking, cavitation plays an important role for the generation of small stone fragments during lithotripsy. Micro-size gas bubbles can be generated due to the presence of the weak spots within biological systems or the passage of the previous strong shock waves. The bubble nucleus are compressed by the compressive part of the shock waves and then expand dramatically generating an intense spherical shock wave, which may significantly influence the behavior of surrounding bubbles and stones. Finally, the bubbles near the stone interface collapse, forming high-speed micro jet with strong erosion ability to fragment the stones.

From left to right: a typical shock wave profile for ESWL; kidney stone before and after ESWL. Adapted from Crum et al. (2008, Fig.1).

Details of bubble cluster collapse at the proximal face of a stone. From Pishchalnikov (2003, Fig.3)

It should be emphasized that if the deliver rate of the shock wave is too fast corresponding to high pulse repetition frequency, energy of shock waves could not be delivered to the stones because of the shielding effects of the bubble cloud, i.e. dissipations of energy through bubble oscillations, generated by previous shock waves.

Fragments of stones after ESWL with different pulse repetition frequency. Adapted from Crum et al. (2008, Fig.2c).

Drawbacks of shock wave lithotripsy are:

SWL could cause many adverse effects e.g. haemorrhages, hypertension, thrombi. It may also lead to long-term damage of the kidney.
The treatment may be uncomfortable and cause pain to the patient if the stone is positioned near a bone or rib because of a mild resonance caused by the shock waves.
The further development of this technique is limited during the past several decades. Comparing with the first commercial lithotriptor Dornier HM3, the other lithotriptors do not show remarkable extra effectiveness.
For large stones (e.g. >10mm), the fragments after SWL are still too large to pass urethra naturally.
Although SWL is effective to treat kidney stones, it has not received general acceptance for treatment of other types of stones (e.g. gallstone, salivary stone).

Nowadays, the use of SWL is waning especially in Europe and USA and many other techniques have been developed e.g. pyeloscopy. As a minimally invasive technique, pyeloscopy inserts a flexible thin fibre-optic telescope (diameter less then 3mm) into the kidney from the bladder via the urethra. The whole kidney system can be visualized. The laser fibers can efficiently smash stones and micro-baskets retrieves the resulting stone fragments. This technique is applicable to the kidney stones up to 20mm in size.

The passage of pyeloscopy. Source

An emerging non-invasive technique using the cavitation generated by the carefully controlled focused ultrasonic waves is being developed (Link in this blog). The strong erosion ability of cavitation cloud during collapse can shatter the stones into much fine powder (approximately <1mm), which can be easily put out of human body.

References
Crum et al. (2008). Cavitation and Therapeutic Ultrasound, Proceedings of WIMRC Cavitation Forum 2008, University of Warwick, UK, pp.10-14.
Leighton, T.G. and Cleveland, R.O. (2009). Lithotripsy, Proc. IMechE Part H: J. Engineering in Medicine, vol. 224, 317-342.
Matsumoto, Y. (2006). Therapeutic application of acoustic cavitation, Proceedings of WIMRC Cavitation Forum 2006, University of Warwick, UK, Chap.3, pp.27-35.
Pishchalnikov (2003). Cavitation Bubble Cluster Activity in the Breakage of Kidney Stones by Lithotripter Shock Waves, J Endourol.September, 17(7): 435–446.

Dolphins and bubbles

2012-05-20T02:48:00.003-07:00

Chinese version

Playing with bubbles is an important part of dolphins' life. It is well known that dolphins enjoy riding waves (e.g. those generated by boats) and jumping between the two bow waves of a moving catamaran.

Bottlenose Dolphin surfs the wake of a research boat on the Banana River near the Kennedy Space Center.From Wikimedia Commons.

Dolphins can also create and manipulate bubbles and show a complex behavior during their play with bubbles. The bubbles generated by dolphins mainly include: bubble stream, bubble burst, bubble cloud, single bubble trail, (sing or double) bubble ring (McCowan et al., 2000). Dolphins can play interactively with those bubble through biting bubbles, swimming through the bubble rings and manipulating the bubble ring using their rostrum (e.g. turning the ring in a vertical fashion). More sophisticated behaviors has been observed during dolphin's play with bubbles, e.g. generation of a second bubble ring which joins the first bubble ring to form a larger bubble ring; generation of the third bubble ring passing through the second ring to catch and join the first ring.

Bubble ring generated by a dolphin. Source

Bubble ring made by a dolphin in the aquarium. From YouTube.

Bubble stream generated by a dolphin. From YouTube.

A burst of bubbles from dolphin blow hole. Source.

Both wild and captive dolphins can blow bubble rings. Sometimes, the size of the bubble ring can be large enough for dolphin to swim through. More interestingly, blowing bubble rings takes practice i.e. those dolphins who can not blow bubble rings can learn it after watching others and taking experiments (Walke, 2008, p.30; video). How smart dolphins are! It has been reported by BBC that two beached whales in New Zealand were rescued by a bottlenose dolphin.

A dolphin passing through the bubble ring. Source.

Although dolphins are talented swimmers, it has been observed that the swim speed of dolphin is below 54 kilometers per hour near the surface. According to a recent study by Iosilevskii and Weihs (2008) (also reported by New Scientist), it is cavitation which limits the speed of the dolphin. Based on a series of calculations, they found that cavitation bubbles could be formed near the tail of dolphin due to the movement of the fins. When the generated bubbles collapse, they will cause damage to the dolphins. Cavitation happens when the speeds of dolphins reach 36 to 54 kilometers per hour near a few meters of the water surface. Different with bony tail of tuna without nerve endings, dolphin can feel the pain if they swim too fast.

References

Iosilevskii, G. and Weihs, D. (2008). Speed limits on swimming of fishes and cetaceans, J. R. Soc. Interface, 5, 329-338. doi: 10.1098/rsif.2007.1073

McCowan et al. (2000). Bubble Ring Play of Bottlenose Dolphins (Tursiops truncatus): Implications for Cognition, Journal of Comparative Psychology, 2000, Vol. l14, No.1, pp.98-106.pdf

Walke, S.M. (2008). Dolphins, Lerner Publishing Group.

2013 International conference on multiphase flow (May, 2013, Jeju Island, South Korea)

2012-05-18T11:18:00.003-07:00

The 2013 ICMF will take place during the last week of May in Jeju Island in South Korea. Professor Moo Hwan Kim of the Pohang University of Science and Technology will be the conference chair.

The details of this conference will be updated on my blog.

ICMF 2010

Cavitation induced by snapping shrimp

2012-05-17T09:02:00.002-07:00

Snapping shrimp (Alpheus heterochaelis), also called pistol shrimp, is usually 3–5 cm in length but it has a remarkably disproportionate large claw, which sometimes is even larger than half of the shrimp's main body. The claw has a pistol-like feature, containing two parts: a protruding plunger (marked as 'pl' in the following figure) and a matching socket (marked as 's' in the following figure). The claw can be rapidly closed, resulting in a high-speed liquid jet containing cavitation bubbles and very loud noise generated during the collapse of the above bubbles. The emitted powerful cavitation bubbles is capable of stunning or kill preys.

Snapping shrimp. YouTube

The structure of claw of snapping shrimp. Reproduced from Versluis,et al (2000).

The process of snapping captured by high-speed camera. Reproduced from Versluis,et al (2000).

The source levels of emitted noise is as high as 190 to 210 dB (peak to peak; referenced to 1 mPa at a distance of 1 m). This severe noise also limit the usage of active or passive sonar underwater. Therefore, snapping shrimp is one of the loudest animals in the sea.

The cavitation bubbles generated by snapping shrimp is so powerful that they can also emit intense flash of light during bubble collapse, termed as shrimpoluminescence. The temperatures inside bubbles during collapse is estimated to be at least 5,000 K.

References

Michel Versluis,et al (2000). How Snapping Shrimp Snap: Through Cavitating bubbles, Science, 289, 2114. DOI: 10.1126/science.289.5487.2114

Detlef Lohse, Barbara Schmitz, Michel Versluis (2001). Snapping shrimp make flashing bubbles, Nature, 413, 477-8.

13th Modern Mathmatics and Mechanics (Oct 6-8, 2012, Shanghai, China)

2012-05-16T04:19:00.000-07:00

http://siamm.shu.edu.cn/Default.aspx?tabid=16919&ctl=Detail&mid=30783&Id=85714

Language: Chinese

100th anniversary of the birth of Wei-zang Chien (钱伟长) will be also celebrated during this conference.

This series conference is mainly organized by Shanghai Institute of Applied Mathematics and Mechanics Link.

Humpback whale's bubble net

2012-05-16T04:06:00.000-07:00

The humpback whale (Megaptera novaeangliae) is a species of baleen whale. The adult ranges in length from 12–16 metres (39–52 ft) and weight approximately 36,000 kilograms (79,000 lb).

A humpback whale shot in water. From Wikimedia Commons.

One of the attractive feeding techniques of humpback whales is the bubble net. A group of whales swim in a shrinking circle and blow bubbles below a school of prey. The formed bubble net confines the school of fish within a limited volume. The diameter of the bubble net could be up to 30 metres (98 ft).

Humpback whale's hunting technique. Video from YouTube.

Bubble ring created by humpback whale. Adapted from National Marine Mammal Laboratory.

Using a crittercam attached to a whale's back, the secret of the talented feeding method of humpback whale has been revealed by National Geography. Firstly, a group of whales dive deep under a school of fish and form a circle. Then they blow their breath out to form a bubble net. Finally, the whales suddenly swim upward through the bubble net with mouths open and swallow a large amount of fish in one gulp. During the process, each humpback has a specialized task, e.g. blowing the bubbles, going down and herding the prey towards the surface and screaming sound to force the prey into the confines of the bubble net.

A recent study by Wiley et al. (2011) (also introduced in ScienceDaily) found more information about the bubble net. Three-dimensional images of whale swimming behavior and bubble release are recreated based on collected data (e.g. depth and orientation in 3-D) using digital suction cup tags attached to whales. They identified a new novel behavior called "double-loops", which consist of one upward spiral to corral the prey and a second upward lunge to capture the corralled prey. The study also reported that at least two individual humpback whales are necessary for bubble net feeding. Furthermore, the humpback whales do not rob the prey from other's bubble nets.

Bubble net formed by humpback whale. Courtesy of Brill.

Humpback whale is not the only talent on the use of bubbles. Dolphins can also make amazing vortex ring, a toroidal shape of a cloud of bubbles moving along the fluids.

Vortex ring by a dolphin. YouTube.

References and further readings

David Wiley, Colin Ware, Alessandro Bocconcelli, Danielle Cholewiak, Ari Friedlaender, Michael Thompson, Mason Weinrich. Underwater components of humpback whale bubble-net feeding behaviour. Behaviour, 2011; 148 (5): 575 DOI: 10.1163/000579511X570893

Mercado E III, Herman LM & Pack AA (2003). "Stereotypical sound patterns in humpback whale songs: Usage and function," Aquatic Mammals 29 (1): 37–52. doi:10.1578/016754203101024068. Retrieved 3 April 2007.

http://www.dosits.org/animals/useofsound/animalsusesound/

8th International Symposium on Heat Transfer (Oct 21-24, 2012, Tsinghua University, China)

2012-05-14T06:27:00.001-07:00

http://www.isht8.net/

This conference is organized by Institute of Engineering Thermophysics, Tsinghua University and is held every four years. The location, Tsinghua University, is one of The World's Most Beautiful College Campuses by Forbes.

The heat and mass transfer across the bubble-liquid interface has been intensively investigated in my Ph.D. thesis. One piece of my works on above topic is being considered to be reported during this conference.

26th IAHR Symposium on Hydraulic Machinery and Systems (August 19-23, 2012, Tsinghua University, Beijing, China)

2012-05-14T06:13:00.000-07:00

http://www.26iahr.org/

This conference will be chaired by world leading expert Prof. Yulin Wu (Tsinghua University, China). Tsinghua University is not only the top university with worldwide reputations but also one of The World's Most Beautiful College Campuses by Forbes. I am sure that you will enjoy your time very well during this conference.

Previously, I studied in Tsinghua University for six years with two and a half years working in the group leaded by Prof. Yulin Wu. Under his supervision, I was fortunately involved in the study of extremely large Francis turbines of Three Gorges Hydropower Station, which is the largest one of its kind across the world.

8th international symposium on cavitation (13th - 16th August 2012, Sinapore)

2012-05-14T05:46:00.002-07:00

Prof. Shengcai Li (University of Warwick, UK; my Ph.D. supervisor) will be a invited speaker of this conference. Abstract

Scope (from website http://www.cav2012.sg/)
CAV2012 is the eighth international symposium on cavitation since 1986. It covers all aspects of cavitation, both fundamental and applied. The aim of the conference is to provide a platform in which the state of the art of the knowledge and control of cavitation and its effects is presented and discussed. Physical insights, numerical modeling and applications, engineering application of cavitation for marine, biomedical, manufacturing and turbomachinery are among the major topics.

The use of ultrasonic cavitation for kidney stone crush

2012-05-14T05:33:00.001-07:00

Large kidney stones can obstruct the urethra and cause severe pain or infection. Current non-invasive approach for kidney stone crush called extracorporeal shock wave lithotripsy (ESWL) has been employed since 1980. In ESWL, multiple shock waves with various pulse repetition frequency (PRF) are used to shatter the stones. For some cases, the resulting stone fragments are too big to pass the urethra, leading to surgical intervention for removal. The shock waves also cause damage of surrounding tissues.

From left to right: a typical shock wave profile for ESWL; kidney stone before and after ESWL. Adapted from Crum et al. (2008, Fig.1).

Fragments of stones after ESWL with different PRF. Adapted from Crum et al. (2008, Fig.2c).

Under support of UK Engineering and Physical Sciences Research Council (EPSRC) Warwick Innovative Manufacturing Research Centre (WIMRC) phase II major project "Non-Surgical Cavitation-Effect Destruction of Kidney Stones" (PI: Prof. Shengcai Li), a non-invasive technique for stone crush using the cavitation generated by the focused ultrasonic waves is being developed. The strong erosion ability of cavitation during collapse can shatter the stones into fine powder (approximately <1mm), which can be easily put out of human body.

Schematic of cloud cavitation control.Adapted from Matsumoto (2006, Fig.3.6).

Collapse of bubble cloud and generated shock wave. Adapted from Matsumoto (2006, Fig.3.10).

Natural kidney stones and fragments after the

ultrasonic irradiation. Adapted from Matsumoto (2006, Fig.3.13).

A three-year Ph.D. Studentship (R.ESCM 9217, ￡79,987) has been awarded to me through above EPSRC Project for theoretical and numerical investigations of central problems identified in this project. For my partial contributions to this project, readers are referred to the Final project report. The main outputs are

1. Computer modelling of the system revealed that modulating the HIFU frequency accelerates the growth of the cavitation bubbles (Zhang and Li, 2011). In simple terms the HIFU transducer frequency follows the resonant frequency of the cavitation bubbles. Compared with a constant HIFU frequency, the bubble growth rate is significantly increased (Li and Zhang, 2011).

2. A novel model based on “front tracking” methods for simulating the dynamics of bubble clouds with a high void fraction, and strong bubble-bubble interaction has been developed (Zhang and Li, 2010b). "Virtual Grid-Based" (VGB) front tracking accounts for bubble coalescence and splitting during DNS (Direct Numerical Simulation) (Zhang and Li, 2010c) and provides much higher accuracy.

3. Additional studies have extended the simulations into the higher frequency regions (MHz frequencies and above) employed by the HIFU transducers and examined the thermal effects of bubble oscillations in liquids (Zhang and Li, 2010a).

4. An improve approach has been proposed for accurate predictions of rectified diffusion near resonance (Zhang and Li, 2011).

5. The effects of liquid compressiblity on radial oscillations of gas bubbles in liquids have been identified (Zhang and Li, 2012).

More related works will be demonstrated in my Ph.D. thesis (available soon).

References

Crum et al. (2008). Cavitation and Therapeutic Ultrasound, Proceedings of WIMRC Cavitation Forum 2008, University of Warwick, UK, pp.10-14.

Matsumoto, Y. (2006). Therapeutic application of acoustic cavitation, Proceedings of WIMRC Cavitation Forum 2006, University of Warwick, UK, Chap.3, pp.27-35.

Zhang, Y. and Li, S. C. (2012). “Effects of liquid compressibility on radial oscillations of gas bubbles in liquids,” Journal of Hydrodynamics, accepted.

Zhang, Y. and Li, S. C. (2010a). “Notes on radial oscillations of gas bubbles in liquids: Thermal effects,” J. Acoust. Soc. Am. 128, EL306-309.

Zhang, Y. and Li, S. C. (2010b). “Virtual grid-based front tracking method,” Engineering Computations, 27, 896-908.

Zhang, Y. and Li, S. C. (2010c). “Direct numerical simulation of collective bubble behavior,” Journal of Hydrodynamics, 22 (Supplement 1), 785-789.

Zhang, Y. and Li, S. C. (2011). “Improved theory for near-resonance bubble rectified diffusion with applications,” 2011 IEEE International Ultrasonics Symposium, Orlando, Florida, USA, October 18-21, 2011 (Poster).

A list of cavitation researchers

2012-05-13T16:22:00.002-07:00

Claus-Dieter Ohl, Nanyang Technological University (NTU), Singapore
http://www1.spms.ntu.edu.sg/~cdohl/home.html
Muthupandian Ashokkumar, University of Melbourne, Australia
http://www.chemistry.unimelb.edu.au/people/ashok.html
Andrea Prosperetti, John Hopkins Unviersity, USA
http://www.me.jhu.edu/prosper/
Andrew Szeri, University of California, Berkeley, USA
http://www.me.berkeley.edu/faculty/szeri/
Thomas Kurz, Universität Göttingen, Germany
http://www.physik3.gwdg.de/~tkurz/
Tom Matula, Washington University, USA
http://www.apl.washington.edu/people/profile.php?last=Matula&first=Tom
Gretar Tryggvason, University of Notre Dame, USA
http://www.nd.edu/~gtryggva/
Yu An, Tsinghua Unviersity, China
http://www.tsinghua.edu.cn/publish/phy/6032/2011/20110106171459009504309/20110106171459009504309_.html
Paul Prentice, University of Dundee, UK
http://imsat.org/PaulPrentice.htm
Luca d'Agostino, Pisa Unviersity, Italy
http://www.spaceatdia.org/index.php?page=d-agostino
John Blake, Birmingham University, UK
http://www.birmingham.ac.uk/schools/mathematics/people/navigation.aspx?ReferenceId=9832&Name=professor-john-blake
Qianxi Wang, Birmingham University, UK
http://www.birmingham.ac.uk/schools/mathematics/people/navigation.aspx?ReferenceId=9860&Name=dr-qianxi-wang
Guoyi Peng, Nihon University, Japan
http://read.jst.go.jp/public/cs_ksh_015EventAction.do?lang_act1=E&code_act1=1000226502&action1=event&judge_act1=2
S. Fujikawa, Hokudai University, Japan
http://mech-me.eng.hokudai.ac.jp/~info/index_e.html
David Sinden, University College of London, UK
http://www.ucl.ac.uk/~ucesdsi/
Gail ter Haar, Institute of Cancer Research, UK
http://www.icr.ac.uk/research/team_leaders/TerHaar_Gail/index.shtml
Steven, L. Ceccio, University of Michigan, Ann Arbor, USA
http://www-personal.umich.edu/~ceccio/index.html
Shengcai Li, Warwick University, UK
http://www2.warwick.ac.uk/fac/sci/eng/staff/scl/
Guoyu Wang, Beijing Institute of Technology, China
http://www.bitliuti.net/index.html

Rectified diffusion

2012-05-13T15:48:00.001-07:00

|Bubbles under acoustic excitation can grow or dissolve due to the mass transfer into/out of the bubbles, termed as rectified (mass) diffusion. As a fundamental phenomenon of acoustic cavitation, rectified diffusion also serves as a paramount effect in many applications, such as bubble sonoluminescence and sonochemistry. For details of this phenomenon, readers are referred to Fyrillas and Szeri (1994, p.381).

Bubble response under acoustic fields with different amplitudes. Adapted from Crum (1980, Fig.4).

Growth of bubble through rectified diffusion. Adapted from Lee (2005, Fig.1).

Recently, the rectified diffusion phenomenon has been investigated during my Ph.D. program with a focus on high-frequency region and near resonance. For example, an improved approach has been proposed for much accurate predictions of rectified diffusion phenomenon near resonance (Zhang and Li, 2011). A dynamic-frequency technique for speeding bubble growth has also been demonstrated and compared with constant-frequency technique (Li and Zhang, 2011). More work has been delivered in my Ph.D. thesis with applications in biomedical engineering.

References

Crum, L. A. (1980). “Measurements of the growth of air bubbles by rectified diffusion,” J. Acoust. Soc. Am., 68, 203-211.

Fyrillas, M. and Szeri, A. J. (1994). "Dissolution or growth of soluble spherical oscillating bubbles," J. Fluid Mech., 277, 381-407.

Lee, J. Kentish, S. and Ashokkumar, M. (2005). “Effect of surfactants on the rate of growth of an air bubble by rectified diffusion,” J. Phys. Chem. B, 109, 14595-14598.

Li, S. C. and Zhang, Y. (2011). “Dynamic-frequency technique for speeding up bubble growth,” Proceedings of WIMRC 3rd International Cavitation Forum, University of Warwick, Coventry, UK, July 4-6, 2011.
Zhang, Y. and Li, S. C. (2011). “Improved theory for near-resonance bubble rectified diffusion with applications,” 2011 IEEE International Ultrasonics Symposium, Orlando, Florida, USA, October 18-21, 2011 (Poster).

Classifications of cavitation

2012-05-13T13:57:00.000-07:00

Cavitation phenomenon can be classified into four categories:

Hydrodynamic cavitation

This type of cavitation is produced when the pressure in the liquid systems (e.g. ship propellers, pumps, turbines, hydrofoils and nozzles) drops below the saturated vapor pressure. Cavitation of hydraulic machinery has been well-documented in Prof. S.C.Li's book (Li, 2000). For most cases, cavitation can cause severe damage to the materials and should be avoided in hydraulic machinery.

Cavitating vortex in the draft tube of a Francis turbine. Adapted from Fig.7.10 of Brennen (1995). Link

(a)

(b)

Cavitation caused damage on the wicket gate (a) and region between wicket gate and crown (b) of Francis turbines, Three Gorges Power Station, China. Adapted from Fig.5&7 of Li(2006).

Acoustic cavitation

This type of cavitation refers to the nucleation, growth and collapse of bubbles under acoustic waves. This kind of cavitation has boosted many interdisciplinary subjects, e.g. sonochemistry, sonoluminescence, sonoporation etc. It has been widely used for kidney stone crush (lithotripsy), gene transfer and non-invasive cancer treatment.

Colour Photograph of the light emitted by a trapped, positionally stable bubble. Frame size is 1 mm×1 mm. Courtesy of R Geisler. Adapted from Lauterborn and Kurz (2010, Fig.70)

Colour photograph of the light emitted by a trapped, positionally unstable bubble. Long exposure. Courtesy of R Geisler. Adapted from Lauterborn and Kurz (2010, Fig.71)

SEM micrographs of cells after sonoporation and fixation. The cells were insonated with 2.25 MHz and 570 kPa peak negative pressure pulses in the presence of MBs. (a) MAT B III cells; (b) red blood cells. Adapted from Mehier-Humbert et al. (2005).

Optic cavitation

This type of cavitation occurs when the medium is radiated by high-intensity laser pulses. Under such extreme conditions, break down of the medium happens and bubbles are formed. High speed camera and holography are usually employed to record the single- or multiple- bubble behavior induced by later.

Single vapor bubble dynamics. The movie is taken with 1 million frames/s, and the image width is 140microns. Courtesy of C.D. Ohl.

Bubble-boundary interaction. Courtesy of C.D. Ohl.

Particle cavitation

Besides photons in optic cavitation, other elementary particles (e.g. protons; neutrinos) can also generate cavitation bubbles. When the high energy particles pass the mediums, a small fraction of mediums will be ionized and rapidly heated, resulting in tiny bubbles.

References
Brennen, C. E. (1995). Cavitation and bubble dynamics. Oxford University Press.pdf
Lauterborn, W. (1980). Cavitation and inhomogeneities in underwater acoustics, Springer-Verlag, pp.3-12.
Li, S. C. (2000). Cavitation of Hydraulic machinery. Imperial College Press.
Li, S.C.(2006). Challenge to Modern Turbine Technologys: Analysis of Damage to Guide Vane Surface of Three Gorge Turbines. Proceedings of 1st Int. Conf. on Hydropower Tech. & Key Equip., Beijing.
Mehier-Humbert,S., Bettinger, T., Yan, F. and Guy,R.H. (2005). Plasma membrane poration induced by ultrasound exposure: implication for drug delivery, J.Control. Release, 104, 213–222.

Shah, Y.T., Pandit, A.B. and Moholkar, V.S. (1999). Cavitation reaction engineering, Kluwer Academic/Plenum Publishers, New York, Chap.1.Link

A list of Books on cavitation

2012-05-10T09:49:00.001-07:00

A list of milestone books on cavitation is given here. The list will be updated. I would also like to help people who are interested in those books but have no available access to them.

Popular science
Young, F. R. (2011). Fizzics: The Science of Bubbles, Droplets, and Foams. Johns Hopkins University Press.

Academic books (ordered following the year)
Brujan, E. (2010). Cavitation in Non-Newtonian Fluids: With Biomedical and Bioengineering Applications. Springer.
Franc, J. P. and Michel, J. M. (2004). Fundamentals of Cavitation. Kulwer Academic publishers.
Young, F. R. (2004). Sonoluminescence. CRC press.
Li, S. C. (2000). Cavitation of Hydraulic machinery. Imperial College Press.
Brennen, C. E. (1995). Cavitation and bubble dynamics. Oxford University Press.pdf
Leighton, T. G. (1994). The acoustic bubble, Academic Press.
Young, F. R. (1989). Cavitation. McGraw-Hill.
Knapp, R.T., Daily, J.W. and Hammitt, F.G. (1970). Cavitation, McGraw-Hill.
Flynn, H. G. (1964). Physics of acoustic cavitation in liquids. In Vol. I, Part B of the series Physical Acoustics, edited by W. P. Mason (Academic Press). a pdf version is available if requested.

My brief CV

2012-05-10T08:34:00.001-07:00

Last updated on 2012.

A brief introduction of me is given below. For a full CV, please contact me through email.

Research interests

Acoustic cavitation: radial oscillations of gas bubbles in the liquids; heat and mass transfer across bubble interfaces; liquid compressibility effects; acoustic cavitation in viscoelastic materials; bubble dynamics under multiple-frequency acoustic excitations; ultrasonic degassing of molten alloys

Hydraulic turbine: cavitation enhancement of silt erosion; fluid structure interaction

Numerical simulations: direct numerical simulation of bubbly flow based on front tracking methods; human upper airway simulations

Selected awards

2011 Chinese Government Award for Outstanding Self-Financed Students Abroad (US$ 6000). Introduction; Research News (School of Engineering, University of Warwick)

2008 Engineering and Physical Sciences Research Council (EPSRC) Warwick Innovative Manufacturing Research Centre (WIMRC) Ph.D. Studentship (R.ESCM 9217, ￡79,987). The whole project (PI: Prof.Shengcai Li) featured in The Engineer; News letter of School of Engineering (Warwick University); Final project report.

2008 Zhonghua Wu Prize for Excellent Student (CNY¥ 2000).Renmin Ribao;
China Science Daily; Journal of Engineering Thermophysics.

Selected refereed journals

1. Zhang, Y. and Li, S. C. (2012). “Effects of liquid compressibility on radial oscillations of gas bubbles in liquids,” Journal of Hydrodynamics, accepted.

2. Zhang, Y. and Li, S. C. (2010). “Notes on radial oscillations of gas bubbles in liquids: Thermal effects,” J. Acoust. Soc. Am. 128, EL306-309.Link

3. Zhang, Y. and Li, S. C. (2010). “Virtual grid-based front tracking method,” Engineering Computations, 27, 896-908.Link

4. Zhang, Y. and Li, S. C. (2010). “Direct numerical simulation of collective bubble behavior,” Journal of Hydrodynamics, 22 (Supplement 1), 827-831.Link

Selected Conference papers

1. Zhang, Y. and Li, S. C. (2011). “Improved theory for near-resonance bubble rectified diffusion with applications,” 2011 IEEE International Ultrasonics Symposium, Orlando, Florida, USA, October 18-21, 2011 (Poster).

2. Li, S. C. and Zhang, Y. (2011). “Dynamic-frequency technique for speeding up bubble growth,” Proceedings of WIMRC 3^rd International Cavitation Forum, University of Warwick, Coventry, UK, July 4-6, 2011.

3. Zhang, Y. and Li, S. C. (2010). “Direct numerical simulation of collective bubble behavior,” Proceedings of 9th International Conference on Hydrodynamics, Edited by Y. S. Wu, S. Q. Dai, H. Liu, et al., China Ocean Press, ISBN 978-7-5027-7834-7, Shanghai, China, Oct 11-15, 2010. Also in Journal of Hydrodynamics, 2010, Volume 22, Issue 5, Supplement 1, 827-831.

4. Zhang, Y., Liu, S., Wu, Y. and Yang, J. (2006). “Calculation of turbulent flow through a Francis turbine with 3D Guide Vanes,” Proceedings I of 1st International Conference on Hydropower Technology & Key Equipment, Beijing, China, Oct 28-30, 2006, pp.351-354.

About this blog

2012-05-07T09:56:00.002-07:00

Nowadays, cavitation phenomenon is increasingly employed in a diverse range of applications, particularly in biomedical and chemical engineering. For therapeutics, cavitation induced by ultrasound irradiations is an important mechanism for many biomedical treatments, e.g. lithotripsy, tissue ablation and transdermal drug transportations. For chemical engineering, a new discipline termed “sonochemistry”, which mainly studies the effects induced by cavitation activities (e.g. nucleation, growth and collapse of bubbles under sonic waves) for facilitating chemical reaction speed, is being intensively investigated by researchers.

The purpose of this blog is to introduce both the physical principles and the emerging technologies involving with cavitation to the public. On this blog, I will not only forward the latest information and technologies of the cavitation research to the readers in an accessible style but also provide many useful resources and links for those professional researchers. Owing to interdisciplinary natures of many cavitation-induced effects, I hope that new connections and collaborations with other researchers can also be established through this blog.

I got to know the term "cavitation" when I was a final-year undergraduate of Tsinghua University (China). Later, as a first-year master student of Tsinghua University, I fortunately participated a joint project between Tsinghua University and Warwick University (UK) to investigate the mechanism of a newly identified cavitation phenomenon in Francis turbines of Three Gorges hydropower station, which is the largest one across the world (Total Capacity: 18,200,000 KW, figure from the website of China Three Gorges Cooperation). In 2008, I became a Ph.D. student of Cavitation Research Group in Warwick University with a three-year Ph.D. studentship under the support of EPSRC WIMRC project “Non-Surgical Cavitation-Effect Destruction of Kidney Stones” to develop a new technology for kidney stone crushing based on cavitation-induced effects. In a word, nearly all my researches during the past several years are related with cavitation, covering both hydrodynamic and acoustic cavitation. Through those activities, I am totally absorbed in cavitation phenomenon, which is the central topic of this blog.

Cavitation

14th European Sonochemistry Society meeting

1st Meeting of the Asia-Oceania Society of Sonochemistry

A bubble journal: Bubble Science, Engineering & Technology

A list of conferences on cavitation and bubble dynamics

1st Meeting of the Asia-Oceania Society of Sonochemistry (July 10-12, 2013, University of Melbourne, Australia)

2013 International conference on multiphase flow (May, 2013, Jeju Island, South Korea)

13th Modern Mathmatics and Mechanics (Oct 6-8, 2012, Shanghai, China)

26th IAHR Symposium on Hydraulic Machinery and Systems (August 19-23, 2012, Tsinghua University, Beijing, China)

10th International conference on hydrodynamics (Oct 1-4, 2012, Saint-Petersburg, Russia)

10th International conference on hydrodynamics (Oct 1-4, 2012, Saint-Petersburg, Russia)

Bubbles in micro- or zero- gravity

Supersonic phenomenon in the kitchen

A list of articles about amazing bubble world

Cavitation-effect lithotripsy

Dolphins and bubbles

2013 International conference on multiphase flow (May, 2013, Jeju Island, South Korea)

Cavitation induced by snapping shrimp

13th Modern Mathmatics and Mechanics (Oct 6-8, 2012, Shanghai, China)

Humpback whale's bubble net

8th International Symposium on Heat Transfer (Oct 21-24, 2012, Tsinghua University, China)

26th IAHR Symposium on Hydraulic Machinery and Systems (August 19-23, 2012, Tsinghua University, Beijing, China)

8th international symposium on cavitation (13th - 16th August 2012, Sinapore)

The use of ultrasonic cavitation for kidney stone crush

A list of cavitation researchers

Rectified diffusion

Classifications of cavitation

A list of Books on cavitation

My brief CV

About this blog

For more information about me, please refer to my linkedin.