Water Flowing (Discharging) Steadily from a Tank
Calculation and equations
Steady state tank discharge calculation is mobile-device-friendly as of August 28, 2014
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Units in Steady State Tank Discharge calculator: cm=centimeter, ft=foot, gal=U.S. gallon, m=meter, min=minute, s=second.
Either the free discharge orifice or the submerged orifice can be modeled. The equations are the same for both cases. A drop-down menu allows you to select circular or square orifice geometry. For a circular orifice, B is orifice diameter. For a square orifice, B is orifice width and height. A drop-down menu allows you to select an orifice type. Discharge coefficients for the four orifice types are built into the calculation. User-defined discharge coefficients are permitted but be sure that Co= CcCv. The calculation only checks to see if inputs are positive; we do not check to see if Co= CcCv.
Built-in values for orifice discharge coefficients
where: A = orifice area, B = orifice diameter or width and height, Cc = contraction coefficient, Cv = velocity coefficient, Co = orifice coefficient = CcCv, g = acceleration due to gravity = 32.174 ft/s2 or 9.8066 m/s2, H = head defined in diagrams above, Q = flow rate (discharge), V = horizontal velocity through orifice, X = horizontal trajectory, Y = vertical trajectory.
Streeter, V. L., E. G. Wylie, and K. W. Bedford. 1985. Fluid Mechanics. McGraw-Hill. 9ed.
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