The flow of liquid and vapor is investigated in trapezoidal and sinusoidal grooves. The effect of variable shear stress along the interface of the liquid and vapor is studied for both co-current and counter-current flows. Velocity contours and results for the friction are obtained for both trapezoidal and sinusoidal grooves. An approximate relation that was previously utilized for the Friction for the liquid was modified to obtain an accurate agreement with the results For trapezoidal and sinusoidal grooves.