VMFL023
VMFL023
Oscillating
Laminar Flow Around a Circular Cylinder
Overview
| Reference |
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| Solver | Ansys Fluent, Ansys CFX | ||
| Physics/Models | Laminar, transient flow | ||
| Input File |
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| Project Files | Link to Project Files Download Page |
Test Case
The purpose of this case is to validate the ability of Ansys Fluent and Ansys CFX to predict the flow structure as well as the reattachment length and Strouhal number against experimental results. The present calculations are confined to the low-Reynolds-number regime (Re = 100), which encompasses unsteady asymmetric flow.
Table 20: Materials, Geometry, and Boundary Conditions
| Material Properties | Geometry | Boundary Conditions |
|---|---|---|
|
Density: 1 kg/m3 Viscosity: 0.02 kg/m-s |
Diameter of the cylinder = 2 m |
U ∞ = 1 m/s |
Analysis Assumptions and Modeling Notes
The flow is laminar, and unsteady. An FFT analysis of the lift coefficient on the cylinder wall is presented to determine the frequency of oscillations. The Strouhal number corresponding to the maximum magnitude of oscillations is presented in the Table below. The formula for the Strouhal number is S = (N * D)/U∞, where N is the frequency, D is the diameter of the cylinder, and U∞ is the freestream velocity.
CFX time duration was chosen to accommodate FFT calculations.
These were chosen based on 
, where 
is the size of the frequency bins and 
is an even divisor of 720720,
as described in FFT documentation.