Xu Wang

Bio: Xu Wang is an academic researcher from Nanjing University of Science and Technology. The author has an hindex of 1, co-authored 1 publications receiving 8 citations.

A spin on cavity formation during water entry of hydrophobic and hydrophilic spheres

Abstract: United States Office of Naval Research (University Laboratory Initiative Grant No N00014-06-1-0445)

Radially expanding/contracting and rotating sphere with suction

Abstract: Purpose This study aims to numerically simulate the flow induced by a radially expanding/contracting and rotating sphere with suction. In the absence of rotation, one-dimensional flow motion occurs as expected. Otherwise, centrifugal force slows down the induced flow motion, in addition to the radial movement of the surface. Design/methodology/approach The present work is devoted to the analysis of a rotating permeable sphere. The sphere, because it is elastic, is allowed to expand or contract uniformly in the radial direction while rotating. Findings Numerical simulations of the governing equation in spherical coordinates are supported by a perturbation approach. It is found that the equatorial region is effectively smoothen out by the wall suction in non-expanding, expanding and contracting wall deformation cases. The radial inward flow in the vicinity of the equator is no longer valid in the case of sphere expansion, and strong suction causes nearly constant radial suction velocities. More fluid is sucked radially inward near the pole region when wall contraction is active. Originality/value The problem is set up for the first time in the literature. It is determined physically, the wall expansion mechanism requires more torque with less drag.

A Numerical Study of a Submerged Water Jet Impinging on a Stationary Wall

Abstract: The impinging jet is a classical flow model with relatively simple geometric boundary conditions, and it is widely used in marine engineering. In recent years, scholars have conducted more and more fundamental studies on impact jets, but most of the classical turbulence models are used in numerical simulations, and the accuracy of their calculation results is still a problem in regions with large changes in velocity gradients such as the impact zone. In order to study the complex flow characteristics of the water flow under the condition of a submerged jet impacting a stationary wall, the Wray–Agarwal turbulence model was chosen for the Computational Fluid Dynamics (CFD) numerical simulation study of the impacting jet. Continuous jets with different Reynolds numbers and different impact heights H/D were used to impact the stationary wall, and the results show that the jet flow structure depends on the impact height and is relatively independent of the Reynolds number. With the increase in the impact height, the diffusion of the jet reaching the impact area gradually increases, and its velocity gradually decreases. As the impact height increases, the maximum pressure coefficient decreases and the rate of decrease increases gradually, and the dimensionless pressure distribution is almost constant. In this paper, the flow field structure and pressure characteristics of a continuous submerged jet impacting a stationary wall are explored in depth, which is of great guidance to engineering practice.