function Re_theta = Van_Driest_Blumer(lambda,Tu)
    % Van Driest and Blumer 1963

    p = [0 1 -1690];

    Re_x = zeros(size(Tu));
    for i = 1:length(Re_x)
        p(1) = 19.6*(Tu(i)/100)^2;
        rr = roots(p);
        Re_x(i) = rr(2)^2;
    end
    
    Re_theta = 0.664*sqrt(Re_x);

end

