Actuator Replication Method for Faster Unsteady Flow Control Computations

This paper describes a new computational strategy for complex aerodynamic flows that involve multiple powered devices, such as flow control actuators or power systems. A complete computational domain contains all the relevant physical regions, including the inner regions of all the powered devices. The proposed strategy aims to reduce the exorbitant computational resources required to resolve fine flow features within most of the devices. The approach involves modifying an existing computational fluid model by introducing a grid generation step and a boundary condition module. The grid generation step employs a predetermined strategy that is performed prior to the simulation step, resulting in a grid system that includes only a few of the devices. The flow computation is then performed by incorporating special boundary conditions replicated over all the powered devices and continually updated in the course of the time-stepping process. This approach demonstrates high computational efficiency, as exemplified by its application to a wing of a rotorcraft equipped with numerous flow control actuators in hover mode. The results obtained using this replication approach closely match those obtained using a complete computational domain, but with approximately 50% fewer computational resources. Excluding many actuators from the computational domain is particularly advantageous for flows with disparate length scales and time scales, enabling practical computations over sufficiently long times.