A combined HDG-FV scheme for inviscid wind gust simulations

Second-order finite volume (FV) methods are still the predominant technique for industrial CFD applications. The meshes used for the simulation of steady state fluid flows have been automated and are designed to capture the required aerodynamic forces. However, these meshes lack the ability to resolve the unsteady features. To address this limitation, additional meshes that are refined along the path of all unsteady features have to be generated. This work proposes a scheme that combines the advantages of both second-order vertex-centred FVs and high-order HDG, to enable the computation of wind gust effects on aerodynamic shapes using the same meshes employed to simulate steady flows within a FV framework. The use of vertex-centred FVs in the vicinity of the aerodynamic shape ensures a minimum number of degrees of freedom when compared to FV methods and it avoids the need for generating a high-order curvilinear mesh. The use of HDG guarantees a low number of degrees of freedom compared to other DG methods. The coupling between both techniques is performed by introducing a set of transmission conditions between the FV and HDG subdomains, thus ensuring conservation.