MATLAB: Plot 2D streamline_issue

contour plotstream2streamline

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

Best Answer

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
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