In order to understand the behaviour of 3D compressible unsteady flow we use URANS. Output processing of particle paths is very valuable, particularly if we include the thermodynamic variables for the particles at each time step. But I know the energy does not simply convect with the mass particles. It can travel 'sideways' by diffusion of heat and also by frictional transfer of work between particles.
Martin,
There are several co-processing output codes that might be able to help you with this. They can track the behavior of fluid elements during the simulation, comparable to vortex tracking. Fieldview is one I particularly recommend. It also depends on what solver you are running. I can connect you with an expert at Fieldview if you contact me via RG messaging.
Dear marilyn, thanks for your reply. I have frequently used commercial software to generate particle paths through a URANS unsteady fölow field. The code I have used is Tecplot it is quite successfull though fails at sliding plane boundarys. However, this is not what I am trying to do here. I do not wish to track the particles of mass. Instead I want to track the energy of the fluid as it moves through the unsteady flow. In a turbomachine the energy exchange of the fluid with the rotor is huge. An HP turbine can have as much as 350 K temperature drop in one inch of travel. So I want to define a new type of particle path: a particle of energy. The energy has at least three mechanisms that allow it to move; convection, diffusion and viscous work. Theses allow the energy to not follow the (mass) particles, but adopt its own path. I hope to gain a better understanding of the fluid flow inside a turbine by comparing the movement of the energy to the movement of the mass.
Fieldview offers co-processing options where you can define variables such as this and track them during the simulation (depending on your solver). The only other option you have is to add the tracking to your solver through the algorithms. You might want to investigate the Intelligent Light website for more info. I hope this helps.
I have found a partial answer to my own question its in the text book A. Bejan "Convection Heat Transfer" defines "Heat lines" to allow the visualisation of convection. All I have to do now is to extend his mathematical definition to include the unsteady work transfer process (dp/dt). Anyone know how to do that?
Martin
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