# How to create a shape in MATLAB

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 January 12, 2013, 17:13 How to create a shape in MATLAB #1 New Member   ananza Join Date: Nov 2012 Posts: 7 Rep Power: 6 Hi guys. I'm a student and I've a homework. If you're gonna help me about that I'll be thankful. I'm studying mechanical engineering. In the lecture of CFD, everybody got a shape of pipe (Actually it's not a pipe. A structure which lets fluid flows inside) We'd to make a 2-d simulation at Star CCM first. Than we must make the same thing in MATLAB and than compare the results. I've already made the Star CCM simulation and got results: Scalar Scene 1_Velocity Magnitude Scalar Scene 2_Pressure Coefficient Vector Scene 1_Cell Relative Velocity Now I've to do the same thing at the MATLAB but I've really no idea how to start. Can you guys please help me? My pipe is: The exercise is: The flow is frictionless, incompressible, stable and irrotational. Fluid is water and entrance velocity is 8 m/s, and d= 1000 Kg/m3 1) The flow function (ψ) for the water passage must be calculated point by point with Laplace-Equation 2) The velocity compenents U and V must be calculated for all the corners. U = dψ/dy, V = -d/dx. 3) The pressure distribution must be calculated with Bernoulli-equation. Especially the pressure coefficient (Cp) must be calculated for all the points. I've some old MATLAB codes from kind of related project %Streamfunction etc. function [psi]=msteinmetz_a() dy=1; dx=1; ymax=40; xmax=2000; yb=25; xb=100; eps=0.00001; dif=eps+1; Uin=0.8; Uout=(ymax-1)*dy/((ymax-yb)*dy)*Uin; psi=zeros(ymax,xmax); %initial distribution for i=1:1:xb-1 for j=2:1:ymax psi(j,i)=psi(j-1,i)+dy*Uin; end end for i=xb:1:xmax for j=yb+1:1:ymax psi(j,i)=psi(j-1,i)+dy*Uout; end end % Finding Stable distribution while (dif > eps) psibefore=psi; for j=2:1:yb for i=2:1:xb-1 psi(j,i)=0.25*(psi(j,i-1)+psi(j,i+1)+psi(j-1,i)+psi(j+1,i)); end end for j=yb+1:1:ymax-1 for i=2:1:xmax-1 psi(j,i)=0.25*(psi(j,i-1)+psi(j,i+1)+psi(j-1,i)+psi(j+1,i)); end end dif=abs(max(max(psibefore-psi))); end %U U=zeros(ymax,xmax); for j=2:1:yb for i=2:1:xb-1 U(j,i)=(psi(j+1,i)-psi(j-1,i))/2*dy; end end for j=yb+1:1:ymax-1 for i=2:1:xmax-1 U(j,i)=(psi(j+1,i)-psi(j-1,i))/2*dy; end end %V V=zeros(ymax,xmax); for j=2:1:yb for i=2:1:xb-1 V(j,i)=(psi(j,i-1)-psi(j,i+1))/2*dx; end end for j=yb+1:1:ymax-1 for i=2:1:xmax-1 V(j,i)=(psi(j,i-1)-psi(j,i+1))/2*dx; end end %Velocity Magnitude Umag=zeros(ymax,xmax); for j=2:1:yb for i=2:1:xb-1 Umag(j,i)=sqrt((U(j,i)^2+V(j,i)^2)); end end for j=yb+1:1:ymax-1 for i=2:1:xmax-1 Umag(j,i)=sqrt((U(j,i)^2+V(j,i)^2)); end end %cp Field cp=zeros(ymax,xmax); for j=2:1:yb for i=2:1:xb-1 cp(j,i)=1-(Umag(j,i)^2)/2*Uin^2; end end for j=yb+1:1:ymax-1 for i=2:1:xmax-1 cp(j,i)=1-(Umag(j,i)^2)/2*Uin^2; end end %plotting subplot(2,1,1) hold on title({'Velocitiy Vectors'}) quiver(U,V); hold off subplot(4,2,5) hold on title({'Streamlines'}) contour(psi,20); hold off subplot(4,2,7) hold on title({'Pressure Coefficient'}) surf(cp); colormap jet; hold off subplot(2,2,4) hold on title({'Streamfunction'}) surf(psi); hold off Last edited by greenfire; January 12, 2013 at 20:37.

 January 17, 2013, 20:41 #2 New Member   ananza Join Date: Nov 2012 Posts: 7 Rep Power: 6 Please help ...

 January 25, 2013, 13:14 #3 New Member   ananza Join Date: Nov 2012 Posts: 7 Rep Power: 6 Bumb bumb .. Please

 February 9, 2013, 18:54 #4 New Member   ananza Join Date: Nov 2012 Posts: 7 Rep Power: 6 Please hellp

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