making a 3d contour

matlab

Answer 1

[Torsten]

pr = 0.734;
n  = 1.413e-5;
ts = 12;
l  = 10;
w  = 4;
k  =0.02428;
V = 10:2:50;
To = 0:10;
for iv = 1:numel(V)
    v = V(iv);
    re = (v * 0.277778 * l) / n;
    nu = (0.037 * re^0.8 - 871) * pr^0.333333;
    h  = (nu*k) / l;
    
    %fprintf("\n\n(velocity : %f(km/h) )\t",v);
    %fprintf(" (rynold : %f)\t",re);
    %fprintf("(nusselt : %f)\t",nu);
    %fprintf(" (h : %f(w/m^2*k))\n",h);
    for ito = 1:numel(To)
        to = To(ito);
        if ts > to
            q(iv,ito) = h * l * w * (ts-to);
        else
            q(iv,ito) = h * l * w * (to-ts);
        end
        %fprintf("\t\t\tthe heat loss from surface is : %f\n", q);
    end
end
[V To] = ndgrid(V,To);
contourf(V,To,q)

surfc(V,To,q)
colorbar

or maybe

n  = 1.413e-5;
ts = 12;
l  = 10;
w  = 4;
k  = 0.02428;
v = (10:2:50).';
to = 0:10;
re = (v * 0.277778 * l) / n;
nu = (0.037 * re.^0.8 - 871) * pr^0.333333;
h  = (nu*k) / l;
q = h .* l .* w .* abs(ts-to);
[V To] = ndgrid(v,to);
contourf(V,To,q)

surfc(V,To,q)
colorbar

[VBBV]

It seems OP wants 3D contour. Perhaps surfc may be good option instead

[Karim Ayman]

Thank you very much.