Discussion Forum

Hi all,

I'm attempting to model reentry speed flow (approx mach 25) over a cone in 2-D axi. It's a stationary model using the high mach number flow, Spalart-Allmaras physics.

The issue I'm having is that when I try to compute i get this error:

Failed to find a solution.
Segregated Step 1
Attempt to evaluate nonintegral power of negative number.
Function: ^
Failed to evaluate variable.
Variable: comp1.hmnf.mu, Defined as: ((comp1.hmnf.mu ref*((comp1.T/comp1.hmnf.Tmu ref)^1.5))*(comp1.hmnf.Tmu ref+comp1.hmnf.S s))/(comp1.T+comp1.hmnf.S s)
Failed to evaluate variable.
Variable: comp1.hmnf.mu eff, Defined as: comp1.hmnf.mu+comp1.hmnf.muT
Failed to evaluate temporary symbolic derivative variable.
Variable: comp1.hmnf.K stress tensor testrzVDN${test3}, Defined as: comp1.hmnf.mu eff
Failed to evaluate expression.
Expression: d(comp1.hmnf.K stress tensor testrz,{test3})
Failed to evaluate Jacobian of expression.
Expression: comp1.hmnf.K stress tensor testrz
Failed to evaluate Jacobian of operator.
Operator: mean, Geometry: geom1, Boundary: 5
Failed to evaluate Jacobian of variable.
Variable: comp1.hmnf.K stress tensor testrz, Geometry: geom1, Boundary: 5
Failed to evaluate Jacobian of expression.
Expression: (2*(comp1.hmnf.KStressn avr*test(comp1.hmnf.u herer)+comp1.hmnf.KStressn avz*test(comp1.hmnf.u herez)+comp1.hmnf.KStressTestn avr*comp1.hmnf.ujumpr+comp1.hmnf.KStressTestn avz*comp1.hmnf.ujumpz-comp1.hmnf.sigma dg ns*comp1.hmnf.unJump*test(comp1.hmnf.un here)+comp1.hmnf.upwind ns+comp1.hmnf.upwindCont+comp1.hmnf.consFlux)*pi*r)*(dvol)
In Turbulence variables:
Returned solution is not converged.

The problem seems to be with this equation: (comp1.T/comp1.hmnf.Tmu ref)^1.5
I'm confused as to how either of these could be negative, as they are both temperatures given in Kelvin.

Any help would be much appreciated