function [ut, vt, wt] = changev(p_x,p_y,p_z,u,v,w)
ut=(u+0.5*p_x.*rand(length(p_z),1)+10)/2;
wt=(w+20*rand(length(p_z),1))/2;
vt=(v+2*sign(2000-p_y).*p_x.*rand(length(p_z),1))/2;
end