how to plot streamline

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Ham Man 2021-7-14

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/878048-how-to-plot-streamline

编辑： Ham Man 2021-7-19

采纳的回答： KSSV

在 MATLAB Online 中打开

I have the 2-D PIV data like below and I am not able to get streamlines in matlab:

ix,iy,iz = image coordinate X,Y,Z [pixel]

dx = displacement component X [pixel] * (image resoltion) = mm

dy = displacement component Y [pixel] * (image resoltion) = mm

--------------------------------------------------

So I have dx and dy in mm. Also I can calculate: du = dx/dt , dv = dy/dt as the velocities in x and y directions.

I want to get the streamline usnig streamline/streamslice functions in matlab but I do not know how to define startx and starty?? Should I use meshgrid function for that? and shoul I use ix,iy(image coordinates) OR dx,dy to define startx and starty points?

Moreover do I need to define meshgrid for du,dv to fill velocities for every point??

Any help would be appreciated.

A = xlsread(......myfile.xls);  % myfile.xls contains all data.
dx = A(1:end,4); % size(dx) = 8400*1
dy = A(1:end,5); % size(dy) = 8400*1
du = A(1:end,6); % size(du) = 8400*1
dv = A(1:end,7); % size(dv) = 8400*1
[startx,starty] = ?????
[X,Y] = meshgrid(dx,dy);
streamline(X,Y,du,dy,startx,starty); 
    

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Ham Man 2021-7-16

The streamline/streamslice gave me an error stating that U,V should be 3D data. How can I make those in 3D?

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采纳的回答

KSSV 2021-7-14

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/878048-how-to-plot-streamline#answer_746358

编辑：KSSV 2021-7-14

在 MATLAB Online 中打开

Try:

skip = 2 ;                  % can be changed 
startx = X(1:skip:end,1:skip:end) ; 
starty = Y(1:skip:end,1:skip:end) ; 
streamline(X,Y,du,dy,startx,starty); 

Also have a look on streamslice. This would be a better function to use.