For any type of orifice, Coefficient of discharge (Cd)= Coeff. of flow/velocity (Cv) × Coeff of contraction (Cc). where Cd = actual discharge/theoretical discharge Cc = Area of vena contract/ area of orifice Cv = actual velocity at vena contract/theoretical velocity Coefficient of velocity is varies between 0.98 to 0.99, and coefficient of discharge is varies between 0.67 to 0.69.