function Re_theta = Langtry_Menter(lambda,Tu)
    % Langtry and Menter 2009

    F = zeros(size(Tu));

    for i = 1:length(F)
        if lambda(i)<=0
            F(i) = 1-(-12.986*lambda(i)-123.66*lambda(i).^2-405.689*lambda(i).^3)...
                *exp(-(Tu(i)/1.5)^1.5);
        else
            F(i) = 1+0.275*(1-exp(-35*lambda(i)))*exp(-Tu(i)/0.5);
        end
    end

    Re_theta = zeros(size(Tu));

    for i = 1:length(Re_theta)
        if Tu(i)<=1.3
            Re_theta(i) = (1173.51-589.428*Tu(i)+0.2196/Tu(i)^2)*F(i);
        else
            Re_theta(i) = 331.5*((Tu(i)-0.5658)^-0.671)*F(i);
        end
    end

end

