Physical Coupling
Multiphysics analysis models the bidirectional exchange of momentum between a moving fluid and a solid body. In electronics cooling and aerospace housing design, fluid-structure interaction describes how high-velocity airflow induces physical deformation or vibration in printed circuit boards and heatsinks. This behavior occurs when the pressure or shear force exerted by the fluid changes the shape of the solid.
The altered solid shape then redirects the fluid flow, creating a continuous feedback loop that affects system reliability.
Stress Analysis
Structural fatigue arises from the oscillatory forces exerted by the moving fluid. When fluid-structure interaction causes boards to flex, the solder joints experience alternating shear stresses. This behavior leads to micro-cracking.
Numerical Simulation
Computational solvers resolve these coupled equations through iterative or simultaneous algorithms. These programs use finite element analysis for the solid domain and computational fluid dynamics for the flow domain. Because solving both domains at each time step requires immense processing power, simplified models are used where the physical displacement is small.
Engineers run these models to check that resonant frequencies of the board do not match the vortex shedding frequencies of the cooling fan. Selecting the correct coupling scheme ensures that the simulation converges without producing artificial instabilities in the numerical output.
