Non-newtonian wind-driven flows in homogeneous semienclosed basins

Wind-driven flow in power-law viscous fluids in homogeneous semienclosed basins is analyzed. Analytical solutions for vertical current profiles for non-newtonian fluids with different power-law indexes are derived assuming a wind shear stress at the surface and zero net transport. Previous classical solutions for wind-driven flows in semienclosed basins are thus generalized. A bidirectional flow in the fluid column is obtained: downwind near the surface and a weaker compensating upwind flow near the bottom. Shear-thickening fluids exhibit larger maximum currents at the surface, although reducing the difference between the maximum current at the surface and the maximum current near the bottom, than newtonian and shear-thinning fluids. The larger the flow behavior index n of the power-law, the more acute the effects. For the same physical conditions (depth, wind shear stress, and flow consistency index), the opposite occurs for shear-thinning fluids. The lower the n value the lower the current at the surface and the larger the differences between the upper and lower layer.