中文摘要：

在随气泡顶端运动的坐标系中,通过将理想流体模型推广到非理想流体的情况,研究了流体黏性和表面张力对Rayleigh-Taylor（RT）和Richtmyer-Meshkov（RM）不稳定性气泡速度的影响.首先得到了RT和RM不稳定性气泡运动的控制方程（自洽的微分方程组）;其次给出了二维平面坐标和三维柱坐标中气泡速度的数值解和渐近解,并定量分析了流体黏性和表面张力对RT和RM气泡速度和振幅的影响.结果表明：从线性阶段到非线性阶段的全过程中,非理想流体中的气泡速度和振幅小于理想流体中的气泡速度和振幅.也就是说,流体黏性和表面张力对RT和RM不稳定性的发展都具有致稳作用.

英文摘要：

In a reference system moving with the bubble vertex we investigate the effects of fluid viscosity and surface tension on the bubble velocity in the nonlinear Rayleigh-Taylor （RT） and Richtmyer-Meshkov （RM） instabilities, by extending the ideal fluid model [Goncharov V N, Phys. Rev. Lett. 88 134502 （2002）] to the non-ideal fluid case. First of all, the governing equation （i.e. self-consistent differential equations） describing the dynamic of the bubble front in RT and RM instabilities is obtained. Then, the numerical and asymptotic solutions of the bubble velocity in two-dimensional planar geometry and three-dimensional cylindrical geometry are obtained. Moreover, we quantitatively study the effects of fluid viscosity and surface tension on the RT and RM bubble velocities. It is found that in the fully nonlinear evolutions of RT and RM instabilities, the bubble velocity and amplitude in the non-ideal fluid are both less than those in its ideal fluid counterpart. That is to say, the effects of fluid viscosity and surface tension tend to stabilize the RT and RM instabilities.