partially filled ellipsoidl horizontal tank volume

i need help in this topic. i calculated the volume of partially filled ellipsoidal tank by the formula
volume of tank = cylinder volume * ellipsoidal volume
cylinder volume = segment area * cylinder length
segment area = R^2*Cos-1((r-h)/r)-(r-h)*(2*r*h-h^2)^.5

v = 0.5362*h^2(1.5d-h) for elipsoidal volume
these are the formula e for volume of tank. i am willing to drive the formula for height against different volume for calibration purpose can some one guide me in this regard.
THANKYOU