Side Discharges into Open Channels: Mathematical Model

The paper presents a three‐dimensional numerical mathematical model for calculating the near field of side discharges into open channel flow. The method employs the standard $k‐\epsilon$ turbulence model for determining the turbulent stresses. Two discretization schemes are considered, namely, the hybrid central/upwind differencing scheme and the quadratic, upstream‐weighted differencing scheme. The latter has been shown by previous investigators to produce improved numerical solutions for a number or recirculating flows. This finding is confirmed by the present investigation. The predictions are compared with experimental observations of earlier investigators of isothermal side discharges into both rough‐ and smooth‐bed open channel flows; each at discharge to cross flow velocity ratios of 0.3 and 4.0. The agreement is in the main, satisfactory for all the different cases considered.