Computation of surface tension and contact angle and its application to water strider

We have developed a new algorithm for the calculation of surface tension and contact angle. This method is applied to the motion of water striders. Two types of movement are found in the experiment and these are analyzed by the simulation. The comparison of these results show that there are two distinct propulsion mechanisms. In the conventional breaststroke type, the leg speed must be larger than phase speed of surface wave which is called Denny's paradox. In a new butterfly type, even the infant water strider can swim and the Denny's paradox is resolved. (c) 2005 Elsevier Ltd. All rights reserved.