Flow containing sediment suspension develops density stratification, due to the tendency for suspended sediment to settle. This damps turbulence and suppresses mixing of momentum and sediment itself. The flow thus has an enhanced velocity gradient and a bias of suspended sediment concentration toward the bed. These tendencies are relevant to bend flow, where suspended sediment is redistributed by secondary flow. This study considers steady, uniform bend flow in a channel with constant width and radius of curvature. The interaction between secondary flow and sediment suspension is examined, as well as the significance of stratification effects. Vertical profiles of velocity and concentration of suspended sediment are solved with the Smith-McLean turbulence closure. The secondary flow structure is then incorporated into the 2D depth-averaged shallow water equations. The level of stratification is characterized by two dimensionless parameters: dimensionless settling velocity and bulk Richardson number.
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