摘要
Based on the fluid motion equations, the physical meaning of eddy viscosity coefficient and the rationality of the Boussinesq hypothesis are discussed in this paper. The effect of the coefficient on numerical stability is analyzed briefly. A semi-enclosed rectangular sea area, with an orthogonal spur dike, is applied in a 2-D numerical model to study the effect of horizontal eddy viscosity coefficient (A(H)), The computed result shows that A(H) has little influence on the tidal level and averaged flow velocity, but has obvious influence on the intensity and the range of return flow around near the spur dike. Correspondingly, a wind-driven current pool and an annular current are applied in a 3-D numerical model respectively to study the effect of vertical eddy viscosity coefficient (A(V)). The computed result shows that the absolute value of A(V) is inversely proportional to that of horizontal velocity, and the vertical gradient value of A(V) determines the vertical distribution of horizontal velocity, The distribution form of A(V) is theoretically recommended as a parabolic type, of which the maximum value appears at 0.5 H.
Based on the fluid motion equations, the physical meaning of eddy viscosity coefficient and the rationality of the Boussinesq hypothesis are discussed in this paper. The effect of the coefficient on numerical stability is analyzed briefly. A semi-enclosed rectangular sea area, with an orthogonal spur dike, is applied in a 2-D numerical model to study the effect of horizontal eddy viscosity coefficient (A(H)), The computed result shows that A(H) has little influence on the tidal level and averaged flow velocity, but has obvious influence on the intensity and the range of return flow around near the spur dike. Correspondingly, a wind-driven current pool and an annular current are applied in a 3-D numerical model respectively to study the effect of vertical eddy viscosity coefficient (A(V)). The computed result shows that the absolute value of A(V) is inversely proportional to that of horizontal velocity, and the vertical gradient value of A(V) determines the vertical distribution of horizontal velocity, The distribution form of A(V) is theoretically recommended as a parabolic type, of which the maximum value appears at 0.5 H.
