Fluid-Structure Interaction Analysis of a Solar Panel Subject to Wind (Vortex Shedding)
In previous technical briefs, we presented the potential-based fluid elements available within ADINA Structures. These elements can model fluid, and its interaction with solid structures, in certain scenarios; while highly accurate and convenient in some cases, the potential-based fluid elements are inviscid and irrotational, and they are not appropriate to model turbulent flows and other complex fluid phenomena.
Here we’re presenting the Computational Fluid Dynamics (CFD) and the Fluid-Structure Interaction (FSI) capabilities in ADINA. Through these, it is possible to accurately model the fluid flow (wind in this example) and turbulence that, in this case, end up causing an alternating fluid pressure on a moving solid structure.
The model in the movie above represents the 2D section of a solar panel (tracker) subject to constant wind speed, blowing from left to right. The panel has been assumed to be rigid and has mass density and dimensions of a real solar panel. A support (rigid in translations and flexible in rotation) controls the overall rotational stiffness and, together with the mass, define the panel's dynamic properties, such as the natural frequency. The wind is modeled as an incompressible Navier-Stokes fluid with the k-ε turbulence model and is discretized using the FCBI-C fluid elements.
Of course, it is also possible to model the flexibility of the panel as well as other elements of the system, whether in 2D or 3D, should this be required.
The results, namely the displacement time history at one tip of the panel, demonstrate the harmonic response. In this case, the periodic steady-sate is reached after a small number of cycles (by defining some appropriate initial conditions) as shown in Figure 1.
Figure 1 Displacement time-history at the right end of the panel
Figure 2 Nodal pressure contours
This is an example of the powerful CFD and FSI capabilities in ADINA. Solar panels are susceptible to suffering dynamic instabilities at specific critical wind speeds and ADINA can help assess many wind speeds and solar panel configurations to limit the risks of catastrophical failure of large parts of solar panel farms, avoiding or reducing the amount of required physical wind tunnel testing.
See also Physical Instabilities in FSI.