Source Panel method for flow pressure distribution over cylinder

In summary, the conversation is about developing a source-panel computer program to numerically calculate the potential flow pressure distribution on a right circular cylinder, with and without circulation. The results will be tabulated and plotted for various values of circulation. The equations and variables needed for the calculations are also discussed, including the difficulty in finding the j components and determining the length of each panel. The person is seeking help with understanding and solving the problem.
  • #1
frozenguy
192
0

Homework Statement


Develop a source-panel computer program to numerically calculate the potential flow pressure distribution on a right circular cylinder with and without circulation.

1.) Tabulate and plot your numerical results for the pressure coefficient distribution on the cylinder together with the corresponding exact analytic solution as a function of the angular variable omega, measured clockwise from the negative x-axis to the center of panels, from 0-360 degrees. Tabulate the following results:
i, omega, q, numerical Cp, theoretical Cp, % error.

2.) Do your calculations for the following values of circulation: K =[itex]\Gamma/\left(2\pi\right)[/itex] = 0, -1, -2, and -3. For K=0 do your calculations for N=4 and 250. For all other values of K, use only N=250.

sourcepanelpicture.jpg


Homework Equations


w=omega
Theoretical Cp=1-4*sin(w)^2
w=(360/N)(i-0.5)
θi= ARCtan((yi+1-yi)/(xi+1-xi))
ζi=0.5(xi+xi+1)
ηi=0.5(yi+yi+1)
yi=sin(wi)
xi=cos(wi)

U0sin(θi - α) =(qi)/2 - SUM^{N}_{j=1}qjcij j does NOT equal i
cij=sin(θi-[itex]\Phi[/itex]ij)/2[itex]\pi[/itex]rijΔS
rij=[(ζij)2+(ηij)2]1/2
[itex]\Phiij[/itex]=ARCtan(ηji)/(ζji)
Sorry but I am making some mistake with the complex symbol program on this forum.

The Attempt at a Solution



I have calculated i, ωi, ηi, ζi, xi, yi, θi for N=250. I can't find the j components of those needed.

Also I'm having trouble finding out the length of each panel. If a square was inside the unit circle, each length would be 1.414 right? But N=250 not 4.
 
Last edited:
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  • #2
So this would be wrong. I'm also having trouble understanding the U0sin(θi-α) part. I've been stuck on this problem for a while. Any help would be much appreciated.
 

1. What is the Source Panel method?

The Source Panel method is a numerical technique used to calculate the flow pressure distribution over a cylinder. It is based on the assumption that the flow can be represented as a combination of uniform flow and a series of discrete sources located along the surface of the cylinder.

2. How does the Source Panel method work?

The Source Panel method works by dividing the cylinder surface into a series of panels. Each panel is assumed to have a source strength, which is determined by solving a system of linear equations using the boundary condition that the flow tangential velocity must be equal to the cylinder surface velocity at each panel. The source strengths are then used to calculate the flow pressure distribution over the cylinder surface.

3. What are the advantages of the Source Panel method?

The Source Panel method has several advantages, including its simplicity and ability to handle arbitrary geometries. It also provides accurate results for both subsonic and supersonic flow regimes. Additionally, the method can be easily extended to consider multiple cylinders or other complex bodies.

4. What are the limitations of the Source Panel method?

One limitation of the Source Panel method is that it assumes the flow is two-dimensional and inviscid, meaning it does not account for boundary layer effects or viscous forces. It also requires a large number of panels to accurately represent the cylinder geometry, which can increase computation time and complexity.

5. How is the accuracy of the Source Panel method evaluated?

The accuracy of the Source Panel method can be evaluated by comparing the calculated results to experimental data or other more complex numerical methods. Additionally, the convergence of the solution can be checked by refining the panel distribution and observing the change in results. Overall, the Source Panel method is considered to be a reliable and accurate method for calculating flow pressure distributions over cylinders.

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