Journal ArticleDOI
Flow past a sphere up to a Reynolds number of 300
T. A. Johnson,V. C. Patel +1 more
TLDR
In this paper, the flow of an incompressible viscous fluid past a sphere is investigated numerically and experimentally over flow regimes including steady and unsteady laminar flow at Reynolds numbers of up to 300.Abstract:
The flow of an incompressible viscous fluid past a sphere is investigated numerically and experimentally over flow regimes including steady and unsteady laminar flow at Reynolds numbers of up to 300. Flow-visualization experiments are used to validate the numerical results and to provide additional insight into the behaviour of the flow. Near-wake visualizations are presented for both steady and unsteady flows. Calculations for Reynolds numbers of up to 200 show steady axisymmetric flow and compare well with previous experimental and numerical observations. For Reynolds numbers of 210 to 270, a steady non-axisymmetric regime is found, also in agreement with previous work. To advance the basic understanding of this transition, a symmetry breaking mechanism is proposed based on a detailed analysis of the calculated flow field.Unsteady flow is calculated at Reynolds numbers greater than 270. The results at a Reynolds number of 300 show a highly organized periodic flow dominated by vortex shedding. An analysis of the calculated vortical structure of the wake reveals a sequence of shed hairpin vortices in combination with a sequence of previously unidentified induced hairpin vortices. The numerical results compare favourably with experimental flow visualizations which, interestingly, fail to reveal the induced vortices. Based on the deduced symmetry-breaking mechanism, an analysis of the unsteady kinematics, and the experimental results, a mechanism driving the transition to unsteady flow is proposed.read more
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An immersed-boundary finite-volume method for simulations of flow in complex geometries
TL;DR: In this paper, a new immersed-boundary method for simulating flows over or inside complex geometries is developed by introducing a mass source/sink as well as a momentum forcing.
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A versatile sharp interface immersed boundary method for incompressible flows with complex boundaries
TL;DR: A sharp interface immersed boundary method for simulating incompressible viscous flow past three-dimensional immersed bodies is described, with special emphasis on the immersed boundary treatment for stationary and moving boundaries.
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The Motion of High-Reynolds-Number Bubbles in Inhomogeneous Flows
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An embedded-boundary formulation for large-eddy simulation of turbulent flows interacting with moving boundaries
Jianming Yang,Elias Balaras +1 more
TL;DR: A non-boundary-conforming formulation for simulating complex turbulent flows with dynamically moving boundaries on fixed Cartesian grids is proposed and the concept of field-extension is also introduced to treat the points emerging from a moving solid body to the fluid.
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A hybrid Cartesian/immersed boundary method for simulating flows with 3D, geometrically complex, moving bodies
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