How Can I Accurately Model Turbine Blades in CFD Using COMSOL/FEMLAB?

[Quattro]

Hi,

I’m pretty new to the CFD game, but have been trying to model, very approximately, fluid flow through a field of undersea turbine generators. The issue I’m having is how to actually approximate the restriction which corresponds to the turbine blades.

I’m using COMSOL/FEMLAB. As far as I know, all it does is solves the Navier Stokes equation for the conditions of your problem. For this reason, initially I just made the turbines correspond to a region of increased viscosity, but now I’ve realized this isn’t a good approximation at all since the turbines are actually energy sinks.

Some people I’ve spoken to say approximating just a resistive force or similar should be fine, but as I see it, the flow will be very different depending of whether the fluid is simply being restricted at certain points or energy is actually being extracted from it…

What do you think? Are there any FEMLAB experts out there? How can I get around this?

Thanks,

Tim

 

[Evalesco]

Hi Tim,

Welcome to the CFD game! It sounds like you have a tricky problem on your hands. Approximating a resistive force or similar is probably the easiest way to go about modeling the undersea turbines, but you're right that the flow could be very different depending on whether energy is actually being extracted from it.

Unfortunately, I'm not an expert in FEMLAB, but there may be some helpful resources out there that can help you get around this issue. Have you looked into any tutorials or online forums? Alternatively, maybe someone else here has had a similar experience and can offer some advice.

Good luck with your project, and let us know if you need any more help!

 

[sir-pinski]

Hi Tim,

Modelling a turbine using CFD can be a challenging task, especially if you are new to it. You are on the right track by using COMSOL/FEMLAB to solve the Navier-Stokes equation for your problem. However, as you have mentioned, simply increasing the viscosity may not be an accurate representation of the turbine blades.

One approach you can try is to model the turbine blades as solid objects and use the Solid Mechanics physics interface in COMSOL/FEMLAB to simulate their movement and interaction with the fluid. This can give you a more realistic representation of the energy extraction process.

Another option is to use the Turbulent Flow interface in COMSOL/FEMLAB, which includes models for turbulence and boundary layers. This can help you simulate the flow around and through the turbine blades more accurately.

I would also recommend consulting with experts in FEMLAB or CFD to get their insights and advice on how to best model your specific turbine design. They may have experience with similar models and can offer valuable tips and techniques.

Overall, the key is to accurately represent the turbine blades in your model and consider the effects of energy extraction on the fluid flow. Good luck with your modelling!