Message 10363

TUFLOW FV
Available since version: 2026.2.0
ERROR 10363 - NaN returned from external turbulence module

Description

The external turbulence module returned a NaN (not-a-number) value for the eddy viscosity or diffusivity. This indicates an instability within the external turbulence closure during the simulation.

Suggestions

Review the turbulence model settings and check the model for numerically extreme conditions such as very large velocities or sharp gradients. Reducing the timestep via the Turbulence Update dt command may help stabilise the solution.

Consider using TUFLOW FV’s internal Vertical Mixing Model == options.