You need map the length and the circumference to your true cylinder.
cylinder_true_length = 20;
cylinder_true_radius = 5;
len_div = linspace(0, cylinder_true_length, 9500);
circum_theta = linspace(0, 2*pi, 5766+1);
[T, L] = meshgrid(circum_theta, len_div);
X = cylinder_true_radius*cos(T);
Y = cylinder_true_radius*sin(T);
Zval = zeros(size(T));
Zval(1:end,1:end-1) = Z;
Zval(:,end) = Z(:,1);
mesh(X,Y,L,Zval,'facecolor','interp')
colormap(jet)
