Warning 1010: Assumptions of UTD not fulfilled

Altair Forum User

I see the following warning:

Warning 1010: Assumptions of UTD not fulfilled

What does it mean and what should I do to fix it?

JIF

For edge diffraction within the UTD context, a largeness parameter K is
defined as

  K = BETA * L * SIN(Alpha_i)^2

with

  BETA     wavenumber 2*pi/lambda

  Alpha_i  angle of the diffraction cone (i.e. angle between incident ray
           and edge)

  L        distance parameter, which for a spherical wavefront can be
           computed from

             L = R*S/(R+S) * sin(Alpha_i)^2

           with
             R = radius of the spherical wavefront
             S = distance of the wave between the diffraction point and
                 the observation point (for double diffraction then the
                 distance between first and second diffraction point)

For the UTD diffraction formulas to be valid, the largeness parameter
K must be larger than 1. If it is too small, then typically the separation
distances for double diffractions are too short, or a MoM region is too close to a UTD edge.

Normally this warning 1010 is not very serious, since the other ray contributions
(direct, reflected ray) would dominate.