176. SIMULATION OF SPATIALLY EVOLVING FLOW PAST A SPHERE IN A STRATIFIED FLUID

Department: Mechanical & Aerospace Engineering
Faculty Advisor(s): Sutanu Sarkar

Primary Student
Name: Matthew Bronson de Stadler
Email: mdestadl@ucsd.edu
Phone: 858-822-0129
Grad Year: 2013

Abstract
High resolution simulation of flow past a sphere in a density stratified fluid is the subject of the present study. Flow past a sphere is an established benchmark problem as it combines fully three-dimensional unsteady flow dynamics with a transition to turbulence. The presence of a density gradient significantly complicates matters as it destroys the symmetry of the problem and introduces a complex coupling between kinetic and potential energy. Applications of the present research include underwater submersibles and flow past mountains in the ocean and atmosphere. The standard approach for numerical simulation of the intermediate to late wake of flow past a body is to use a temporal approximation to relate time evolution in an auxiliary domain not resolving the body to distance downstream of the body in a spatial frame. Very few simulations resolving the sphere in the computational domain have been performed and those that have are characterized by low Reynolds number or the use of turbulence models. The goal of the present study is to simulate spatially evolving flow past a sphere at high Reynolds number without the use of turbulence models. The main objective of this research is to characterize the near to intermediate wake region as density stratification effects begin to become significant. Statistics of interest include the drag coefficient, separation angle, Strouhal number, and the spatial evolution of the velocity fluctuations and the wake defect velocity. In addition to quantitative statistics, visualizations of vortical structures and the internal wave field in the wake are provided.

Related Links:

  1. http://ieng9.ucsd.edu/~mdestadl/

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