A hydraulic jump is a sudden, rapid transition from a supercritical flow to a subcritical flow. At large inflow Froude numbers, the jump is characterized by a significant amount of entrained air. For this paper, the bubbly two-phase flow properties of steady and strong hydraulic jumps were investigated experimentally. The results demonstrate that the strong air entrainment rate and the depth-av...

The authors explore the theoretical and empirical relationship between the nonlocal quantities of the entrainment ratio E, the appropriately depthand time-averaged flux coefficient G, and the bulk Froude number Fro in density currents. The main theoretical result is that E 5 0.125 G Fr 2 o(C 3 U /CL)/cosu, where u is the angle of the slope over which the density current flows, CL is the ratio t...

Self-similarity has been the paradigmatic picture for the pinch-off of a drop. Here we will show through high-speed imaging and boundary integral simulations that the inverse problem, the pinch-off of an air bubble in water, is not self-similar in a strict sense: A disk is quickly pulled through a water surface, leading to a giant, cylindrical void which after collapse creates an upward and a d...

We present an asymptotic preserving (AP), large time-step scheme for the shallow water equations in the low Froude number limit. Based on a multiscale asymptotic expansion, the momentum fluxes are split into a nonstiff and a stiff part. A semi-implicit discretisation, where the nonstiff terms are treated explicitly and stiff terms implicitly in time, is crucial to achieve the AP property. A com...

in this research, the numerical method of computational fluid dynamics and dimensionless parameter of froude number have been applied to determine the flow regime over ogee spillways.froude number is a dimensionless dynamic parameter calculated using the square root of the ratio of inertia force and gravitational force. considering that the study of the regimes of flow over hydraulic structures...

A technical obstruction preventing the conclusion of nonlinear stability of large-Froude number roll waves of the St. Venant equations for inclined thin film flow is the ”slope condition” of Johnson-Noble-Zumbrun, used to obtain pointwise symmetrizability of the linearized equations and thereby high-frequency resolvent bounds and a crucial H nonlinear damping estimate. Numerically, this conditi...