Dispersion of Buoyant Waste Water Discharged from Outfall Diffusers of Finite Length

The three-dimensional flow field created by a simple line plume of finite length in a steady current of uniform density was investigated in a laboratory basin. The results can be used to aid in the prediction of dispersion of buoyant waste water released from line diffusers, particularly sewage discharges into the ocean. The experimental results for minimum surface dilution, Sm, were found to be independent of L/H, in the range 3.7 < L/H < 30 where L is the diffuser length and H the water depth, and independent of Reynolds number, Re = 4uH/v, in the range 1190 < Re < 12,900 where u is the current velocity. The results are expressed graphically in the form: Smq/uH = f(F,θ) where q is the volume…