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Error while using time-dependent study
Posted 2026年1月15日 GMT+9 20:51 Computational Fluid Dynamics (CFD), Molecular Flow Version 6.3 1 Reply
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Hello, I get the error
" Complex value found in discontinuous Galerkin evaluation. -Expression:(comp1.cee.gamma_rho)*1-(0)" while using explicit Runga-Kutta method
and "BDF solver does not support discontinuous Galerkin." while using Implicit BDF solver
I am working on High Mach number flow, Laminar and Compressible Euler equations for supersonic expansion in different types of nozzles . I encounter these errors only in time dependent study. The stationary study works perfectly fine.
Is there anyway to solve these errors?
Thank you.
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Dear Akhila Jose,
I recommend creating a support case via https://www.comsol.com/support so that we can assist you directly.
The model file you attached does not include the time-dependent study. Could you please provide this as well? This would allow us to review how the study has been set up.
Please note that the Compressible Euler Equations interface is based on the discontinuous Galerkin method (dG-FEM) and uses a time-explicit solver (see https://doc.comsol.com/6.4/docserver/#!/com.comsol.help.cfd/cfd_ug_fluidflow_high_mach.08.25.html). As a result, an implicit time-stepping method such as BDF cannot be used with this interface.
Best regards, Moritz Becker
