I am planning to simulate a natural circulation loop dynamics in Ansys Fluent. The fluid (water) in the loop is initially at rest and initiates flow upon heating at a section. For such a system with turbulence modelling, how to specify the initial guess of turbulent parameters? I am using SST K-w model for turbulence modelling.
Which one should I follow?
- Intensity and length scale
- Intensity and hydraulic diameter
You can choose any one, the select depends on the Information you have.
the best is the intensity and hydraulic diameter
You can choose any one, the select depends on the Information you have.
the best is the intensity and hydraulic diameter
Hi,
so by the given facts, your fluid is initially at rest and therefore it is initially not turbulent. Consequently it would be a false specification which could potentially affect your obtained results, if you would specify turbulence initial conditions, which would result in a rather large eddy viscosity (making the fluid at rest artificially much to viscous and thereby disturbing its acceleration from rest into motion).
From the two options, you probably can go with either one of those. The most crucial is, that you specify a rather low turbulence intensity, lets say 0,01%. As low as the flow solver will tolerate for the first timesteps of your simulation. If the fluid is getting in motion by natural convection and buoyancy, than a more justified level of turbulence will develop by its own, once the fluid comes up to its final recirculation speed.
- Badges
- Science topic