Hi everyone,

I’m running a transient internal flow simulation in SOLIDWORKS Flow Simulation 2025 for a closed-loop water piping system. The goal is to predict warm-up time due to pump work and frictional (viscous) heating.

In older guidance and online references, I’ve seen repeated mentions of enabling “High Mach Number Flow” to ensure frictional heating / viscous dissipation is included. However, in my case:

• Fluid: liquid water
• Flow regime: low-speed, incompressible
• Analysis type: internal, transient, temperature solved
• Turbulence enabled (laminar + turbulent)

I do not see a “High Mach Number Flow” option anywhere in the Flow Simulation Wizard or General Settings in the 2025 version.

My questions are:

1. In SOLIDWORKS Flow Simulation 2025, is viscous (frictional) heating for incompressible liquid flows included automatically when solving the transient energy equation?
2. Is the “High Mach Number Flow” option now limited to compressible gas flows, and therefore hidden/irrelevant for liquid cases?
3. Is there any additional setting required to ensure pressure losses and pump work are converted into thermal energy for liquid internal flows?

For context, pumps are modeled using pressure jump boundary conditions, and heat loss to ambient is modeled via a convection boundary condition on the pipe walls.

Any clarification on how frictional heating is handled in current versions would be greatly appreciated.

Thanks in advance!