Hi,
I am working on a flow simulation study where I am investigating the presence an severity of turbulence in a section of piping. To do this I wanted to look at the Reynolds number in a number of subsections to get an initial idea if turbulence is present at all.
To determine the Reynolds number in different sections of the system, I have made volume goals for the average fluid density, the average fluid velocity and the average dynamic viscosity of the fluid. I used these volume goals in an equation goal where I included the piping diameter as the characteristic length.
The issue that I keep running into at the moment is that volume goal for the dynamic viscosity is consistently around 0.0007-0.0008 Pa*s. With these values for the dynamic viscosity, I end of up with Reynolds number is in the region of 190000 to 210000 which is massively higher than a value that I would consider to be reasonable for the scenario.
I have made a reference calculation by hand using density and viscosity values from the internet and ended up with a Reynolds number of 90000.
I am using water at 20 deg C from the built-in engineering database, so the input data for the fluid in question should be correct. I have also double checked this data and did not find any values that are out of the ordinary.
3 question that I have about this are:
- What could be causing this discrepancy in the dynamic viscosity?
- The hand calculation for the Reynolds number also seems quite high to me so I am also wondering if there is a more suitable dimension to use as the characteristic length?
- As far as I am aware, the RANS solver that SW uses cannot really resolve turbulence as such, so the Reynolds number is to my knowledge the best way to do this. Does anyone know of another method to check for turbulence presence and severity in SW flow simulation?
