HEC-RAS 2D Sediment Technical Reference Manual Model Description Total-load Transport Equation Current: Vertical Diffusion Coefficient PDF Download PDF Download page Vertical Diffusion Coefficient. Current page All pages Vertical Diffusion Coefficient The vertical diffusion coefficient is required for determining the suspended-load correction factor. The vertical sediment diffusion coefficient is assumed to be related to the turbulent eddy viscosity as\varepsilon _{vk}=\frac{\nu _{tv}}{\sigma _{sk}}whereε_{vk } = \text{vertical sediment diffusion coefficient (diffusivity) }[L^2/T]ν_{tv } = \text{vertical turbulent eddy viscosity (diffusivity) }[L^2/T]σ_{sk } = \text{Schmidt number [ - ]}The vertical turbulent eddy viscosity is computed asν_{tv} = c_{Mv}u_*hwherec_{Mv } = \text{empirical coefficient ( ≈ κ/6) [ - ]}u_{* } = \text{total bed shear velocity }[L/T] h_{} = \text{water depth }[L] ×