Mechanism Study and Bionic Design of Water Running of Basilisk Lizard

When running on water surface, basilisk lizard will pull its foot upward before the air cavity closes and adjust position to adapt to the unsteady fluid field. To obtain the mechanism of water running, the hydrodynamic model of foot to enter water and come out of water is presented, in which the coming-out-of-water process is considered. Combined with RNG (renormalization group) k-ε turbulence equation, the optimal time of coming-out-of-water is obtained by analyzing expansion and contraction of air cavity. In view of adjustment of foot position, 3-dimensional driving forces changing with angle of entering water are analyzed, and the function between lift force and velocity is derived. By experiment, it is validated primarily that the numerical model is correct. For the bionic basilisk lizard, a water surface vector propeller is designed with transforming foot movement into impeller rotation, and the dimension of driving force is increased. The hydrodynamic model of the propeller is established to analyze the influence of impeller quantity on mechanical property. In the experiment of propeller application, the water surface device realizes hydroplaning navigation with pitch angle 10.6°.