Plot 2D streamline_issue

I need a help to plot 2D streamline along with the contour plot. I am unable to plot the steamline properly(startx,stary). I am attaching my plot in the figure. It is starting from the middle for some reason. kindly help me to solve it. I am attaching the data files for your refernce to test it.

   navg = 11;
filenames = cell(navg,1);
for i = 1:navg
    filenames = sprintf('queen2_test_%d.txt', i);
    mydata{i}=importdata(filenames);
    %     writematrix(avg_mat{i}, filenames{i});
    R = mydata{i}(:,1);%X
    C = mydata{i}(:,2);%Y
    U = mydata{i}(:,3);
    V = mydata{i}(:,4);
    F = mydata{i}(:,7)./5;%F(X,Y)
    F(isnan(F)) = 0;
%     F = max(F,0);
    rg = linspace(0, max(R), 100);
    cg = linspace(0, max(C), 100);
    [Rg, Cg] = meshgrid(rg, cg);
    Fg = griddata(R, C, F, Rg, Cg);
   Ug = griddata(R, C, U, Rg, Cg);
   Vg = griddata(R, C, V, Rg, Cg);

    figure
     ax = axes();
    caxis([-5 5])
    colorbar
    ax.YDir = 'reverse';
%     ax.Position(2) = ax.Position(2)+0.02;
    hold on;
  [CC,HH] = (contourf(Rg,Cg,Fg));
  set(HH,'LineColor','none')
%       contourf(peaks(20),10,'edgecolor','none');
     colormap(bluewhitered);
      ax.XAxisLocation = 'top';
%     cb = colorbar('Location', 'south');
%     cb.Position(2) = cb.Position(2)-0.11;
    grid on;
    hold on
    xstart = linspace(.025, max(R),300);
    ystart = .005*ones(size(xstart));
    s = streamline(Rg,Cg,Ug,Vg,Rg,Cg,[0.1,10000]);
%      s = streamline(Rg,Cg,Ug,Vg,xstart,ystart,[0.1,10000]);
%     [s.Color] = deal('g');
  quiver(R,C,U,V);

end

[Ameer Hamza]

variable Ug and Vg are also not defined in this code. Can you give the code with generates the figure in question?

Answer 1

[Ameer Hamza]

Try this code

navg = 11;
filenames = cell(navg,1);
for i = 1:navg
    filenames = sprintf('queen2_test_%d.txt', i);
    mydata{i}=importdata(filenames);
    R = mydata{i}(:,1);%X
    C = mydata{i}(:,2);%Y
    U = mydata{i}(:,3);
    V = mydata{i}(:,4);
    F = mydata{i}(:,7)./5;%F(X,Y)
    rg = linspace(0, max(R), 100);
    cg = linspace(0, max(C), 100);
    [Rg, Cg] = meshgrid(rg, cg);
    Fg = griddata(R, C, F, Rg, Cg);
    Ug = griddata(R, C, U, Rg, Cg);
    Vg = griddata(R, C, V, Rg, Cg);
    
    figure
    ax = axes();
    caxis([-5 5])
    colorbar
    ax.YDir = 'reverse';
    hold on;
    contourf(Rg,Cg,Fg);
    colormap(bluewhitered);
    ax.XAxisLocation = 'top';
    grid on;
    hold on
    quiver(R,C,U,V)
    %%%%% streamline plot section start
    xstart = linspace(0, max(R), 50);
    ystart = 0.004*ones(size(xstart));
    s = streamline(Rg,Cg,Ug,Vg,xstart,ystart);
    %%%%% streamline plot section end
    axis([0.02 0.07 .01 0.1])
    set(gca,'XTick',0.02:.02:.07)
    set(gca,'XTickLabel',0.2:0.2:.7)
    set(gca,'YTick',0:.02:.1)
    set(gca,'YTickLabel',0:0.2:1)
    xlabel('x/c')
    ylabel('y/c')
    h = colorbar;
    pos = get(h,'Position');
    h.Label.Rotation = 0;% to rotate the text
    h.Label.Interpreter = 'latex';
    h.Label.String = '$\ C_{p}$';
    set(gca, 'Color', 'black');
    %saveas(gcf,filenames(1:end-4),'png');
    exportgraphics(gcf,[filenames(1:end-4),'.png'], 'Resolution', 600);
    delete(gcf);
end

[MS]

Thank you very much. I need few request in the plot. I could see only part of the stream line comapred to the quiver arrows as shown in the attached figure. Kindly let me know the possibility to change the colur and show arrow marks in the stream line.

Also, I need a consistent black colur line around the plot. Please let me know if you know the solution for it.

[Ameer Hamza]

I couldn't find a way to overlap the streamline and the quiver arrow.

To change the colors of quiver arrow, you can do something like this

q = quiver(R,C,U,V, 'Color', 'r');

and for streamlines, you can change color like this

s = streamline(Rg,Cg,Ug,Vg,xstart,ystart);
[s.Color] = deal('r');

To create black like around the axes, you can try to run

box on

after creating the axes.

[MS]

Thank you. Kindly let me know how to export as a mat lab figure(.fig) in the above code.

 exportgraphics(gcf,[filenames(1:end-4),'.fig'], 'Resolution', 600);%not working for me

I am trying to fill the stream line by follwing method as of now. It is helping bit but not completely.

xstart = linspace(0, max(R), 500);% incresing the values
    ystart = 0.005*ones(size(xstart));
    s = streamline(Rg,Cg,Ug,Vg,xstart,ystart,[0.1,20000]);% incearing the last number in this line

[Ameer Hamza]

To save as .fig file use savefig(): https://www.mathworks.com/help/releases/R2020a/matlab/ref/savefig.html

I am not sure about filling the streamlines. I haven't used this function quite often.

[MS]

Thank you ameer. I am able to save the .fig files using the follwing command line as you suggested.

savefig([filenames(1:end-4),'.fig']);

I will update a command line if i am able to make any progress about the stream line.

[MS]

I tried to increase the numbers. Still, i get the same issue here.

xstart = linspace(0, max(R), 1000);
    ystart = 0.005*ones(size(xstart));
    s = streamline(Rg,Cg,Ug,Vg,xstart,ystart);
    [s.Color] = deal('g');