加減速を伴うマイクロバブルを含む水流に関する非線形音響理論の基礎研究

抄録

The present study theoretically deals with two types of weakly nonlinear (i.e., finite but small amplitude) propagations of pressure waves in water flows containing many spherical microbubbles, especially focusing on the effect of a nonuniform distribution of flow velocity. By using the method of multiple scales with appropriate choices of the set of scaling relations composed of three nondimensional ratios, the Korteweg-de Vries-Burgers equation for a low frequency long wave and the nonlinear Schrödinger equation for a high frequency short wave can be derived as nonlinear wave equations with variable coefficients. Hence, we succeeded the extension of our previous result for quiescent bubbly liquids into the case of bubbly flows with nonuniform flow velocities.