f=tfvfunct(x)

function f=tfvfunct(x)

nu=1.4e-3; 
Dp = 5e-3; 
rho2 = 1260; 
rho1 = 1042; 
g = 9.81;

if x<2
    f=1/(18*nu)*Dp^2*abs(rho2 - rho1)*g;
elseif x >= 2 & x < 500
    f=x*nu/(Dp*rho1);
else    f=sqrt((3*abs(rho2 - rho1)*Dp*g)/rho1);
end

end