Biofluiddynamics    Drops    Bubbles    Soft Matter    Nanofabrication   


How do insects jump on earth and water?

We study how aquatic insects, such as water striders, can jump on water without sinking. Along with the theoretical approach, we observe the jumping behavior of cylinders and spheres on water. We are currently extending our interests to the jumps of terrestrial insects.

Related publications
1. D. Vella, D.-G. Lee, and H.-Y. Kim, “Sinking of a horizontal cylinder,” Langmuir 22, 2972-2974 (2006)
2. D. Vella, D.-G. Lee, and H.-Y. Kim, “The load supported by small floating objects,” Langmuir 22, 5979-5981 (2006)
3. D.-G. Lee and H.-Y. Kim, “Impact of a superhydrophobic sphere onto water,” Langmuir 24, 142-145 (2008)
4. D.-G. Lee and H.-Y. Kim, “The role of superhydrophobicity in the adhesion of a floating cylinder,” Journal of Fluid Mechanics 624, 23-32 (2009)
5. D.-G. Lee and H.-Y. Kim, “Sinking of small sphere at low Reynolds number through interface,” Physics of Fluids 23, 072104 (2011)
6. E. Yang and H.-Y. Kim, “Jumping hoops,” American Journal of Physics 80, 19-23 (2012)
7. J.-S. Koh, E. Yang, G.-P. Jung, J. H. Son, S.-I. Lee, P. G. Janblonski, R. J. Wood, H.-Y. Kim, and K.-J. Cho, “Jumping on water: Surface tension-dominated jumping of water striders and robotic insects,” Science 349, 517-521 (2015)
8. E. Yang, J. H. Son, S. Lee, P. G. Jablonski and H.-Y. Kim, “Water striders adjust leg movement speed to optimize takeoff velocity for their morphology,” Nature Communications 7, 13698 (2016)
9. H.-Y. Kim, J. Amauger, H. B. Jeong, D.-G. Lee, E. Yang, and P. G. Jablonski, “Mechanics of jumping on water,” Physical Review Fluids 2, 100505 (2017)

Cover of the January issue of American Journal of Physics (2012): Ref. 6

Flapping foils and fluttering flags

We study this interesting problem of flow-structure interaction by coupling simple but innovative theory with high-speed visualization experiments in wind and water tunnel.

Related publications
1. Y.-J. Park, U. Jeong, J. Lee, S. R. Kwon, H.-Y. Kim, and K.-J. Cho, “Kinematic condition for maximizing the thrust of a robotic fish using a compliant caudal fin,” IEEE Transactions on Robotics 28, 1216-1227 (2012)
2. J. Lee, Y.-J. Park, U. Jeong, K.-J. Cho, and H.-Y. Kim, “Wake and thrust of an angularly reciprocating plate,” Journal of Fluid Mechanics 720, 545-557 (2013)
3. J. Bae, J. Lee, S. M. Kim, J. Ha, B.-S. Lee, Y. J. Park, C. Choong, J.-B. Kim, Z. L. Wang, H.-Y. Kim, J.-J. Park & U.-I. Chung, “Flutter-driven triboelectrification for harvesting wind energy,” Nature Communications 24, 4929 (2014)
4. J. Lee, H. Choi, and H.-Y. Kim, “A scaling law for the lift of hovering insects,” Journal of Fluid Mechanics 782, 479-490 (2015)
5. J. Lee, Y.-J. Park, K.-J. Cho, D. Kim, and H.-Y. Kim, “Hydrodynamic advantages of a low aspect-ratio flapping foil,” Journal of Fluids and Structures 71, 70-77 (2017)

Optimal structures in nature

Related publications
1. K. Park, W. Kim and, H.-Y. Kim, "Optimal lamellar arrangement in fish gills," Proceedings of the National Academy of Sciences of the United States of America 111, 8067-8070 (2014)
2. S. Jung, E. Yang, W. Jung, and H.-Y. Kim, "Anti-erosive mechanism of a grooved surface against impact of particle-laden flow," Wear 406-407, 166-172 (2018)
3. K. Park, Y. Jung, T. Son, Y.-J. Cho, N. L. Jeon, W. Kim, and H.-Y. Kim, "Optimal diameter reduction ratio of acinar airways in human lungs," PLoS ONE 14, e0204191 (2019)
4. Y. Jung, K. Park, K. H. Jensen , W. Kim, and H.-Y. Kim, "A design principle of root length distribution of plants," Journal of the Royal Society Interface 16, 20190014 (2019)

Cover of the December issue of Journal of the Royal Society Interface (2019): Ref. 4