
If the Erosion/Accretion option is selected in the Discrete Phase Model panel, the erosion rate expression must be specified at the walls. The erosion rate is defined in Equation 22.51 as a product of the mass flux and specified functions for the particle diameter, impact angle, and velocity exponent. Under Erosion Model in the Wall panel, you can define a constant, polynomial, piecewiselinear, or piecewisepolynomial function for the Impact Angle Function, Diameter Function, and Velocity Exponent Function ( , , and in Equation 22.51). See Sections 22.5 and 22.11.5 for a detailed description of these functions and Section 8.2 for details about using the panels for defining polynomial, piecewiselinear, and piecewisepolynomial functions.