Project “Numerical Flow Visualization” using the commercial program Star-CD CCM+

Martinus Susilo 2221237

Part 1. Flow about circular cylinder

Case 1. Steady, Incompressible laminar flow, Re = 89, D = 0.02 m, u = 0.07

Another physical Model: 2-D, stationary, gas, segregated flow, constant density, steady, inviscid flow

.

Strouhal Number The Strouhal number is a dimensionless number describing oscillating flow mechanisms.

Reynolds Number

Where

Drag Coefficient (Cd)

Where

For air,

Answer

1. The flow for this case is attached. 2. The flow is steady.

3. Drag D = 0 N , Drag Coefficient

4. No, there is no periodic vortex shedding. 5. No frequency.

Comments: Figure 1 shows Inviscid flow over a sphere. Under this condition, the viscosity is neglected, the no-slip condition at the surface of the cylinder does not apply the fluid simply and very small (can be neglected) drag results. (Fluid is frictionless). Also in the absence of vorticity (inviscid flow), flow separation cannot occur. It results symmetric flow front to back because the mass flow between any two streamlines is constant, wherever streamlines open up, the velocity must decrease, and there is no net drag force due to pressure. But the flow has tendency to act asymmetry. The residual plot start to oscillate(converged) from 1300th iteration. The Ball experience no drag

The result starts to converged (residuals are not changing), the graphs are “stable” or same pattern or periodic from 1300th Iteration.

Residuals:

Literatures: ://www.centennialofflight.gov/essay/Theories_of_Flight/Skin_Friction/TH11G2.htm ://www.allstar.fiu.edu/aero/Flow1.htm W.Fox, Robert, McDonald, Alan T., Pritchard, Philip J., Introduction to Fluid Mechanics, John Willey & Sons, Inc. New York, 2006