Separation in overflow spillways may occur when the hydraulic head is considerably greater than the design head. In this study, results obtained in a separation that occurred in a physical model were used for a numerical analysis of the phenomenon. A three-dimensional computational programme was used and the results using none or one of six different turbulence models were compared to the experiment. The results indicate that the renormalization group (RNG) model has a better capacity to simulate the separation zone; therefore, this turbulence model is recommended. Once separation still occurred when no turbulence model was used, the use of non-appropriate models may conceal the phenomenon. This is a computational indication that viscous effects have no major part in this separation condition, with the spillway profile being the most decisive aspect. When RNG was the applied model for several different hydraulic heads, good agreement in terms of discharge coefficient between numerical and physical model was obtained.

当水头远大于设计水头时，溢流道可能会发生分离。在这项研究中，在物理模型中发生的分离中获得的结果用于对该现象进行数值分析。使用了一个三维计算程序，并且将不使用或使用六种不同湍流模型之一的结果与实验进行了比较。结果表明，重整化群（RNG）模型具有较好的分离区模拟能力；因此，推荐使用这种湍流模型。一旦在没有使用湍流模型的情况下仍然发生分离，使用不合适的模型可能会掩盖这种现象。这是一个计算表明粘性效应在这种分离条件中没有主要作用，溢洪道剖面是最具决定性的方面。当RNG作为几种不同水头的应用模型时，数值模型和物理模型在流量系数方面得到了很好的一致性。