Experimental and numerical study on wave characteristics by a moving submerged body in a two-layer fluid

Abstract

Waves induced by an immersed moving body in a two-layer fluid were studied experimentally and numerically. Unmixed fluids (water and cooking oil) were used as the two-layer fluid. A submerged body was manufactured to move with a wire loop system connected to the motor. The measured data were compared with numerical results and theoretical solutions. Numerical calculations were performed using the computational fluid dynamics (CFD) program. The characteristics of the generated waves, such as wave patterns and wavelengths, were qualitatively similar to the numerical results and theoretical values. Of the two wave propagation modes in a two-layer fluid, the baroclinic mode was dominant when the immersed body moved at a low speed. In contrast, the barotropic mode became more prominent as the body velocity increased. Based on these characteristics, transverse waves dominated when the velocity of the body was low, and divergent waves became more distinct as the velocity increased. In addition, the fluid depth and the location of a submerged body can affect the characteristics of the wave patterns.