Zonal Immersed Boundary Conditions: Application to a High-Reynolds-Number Afterbody Flow

Abstract

The present paper focuses on a new numerical strategy consisting of the zonal use of the immersed boundary conditions combined with the ability of zonal detached-eddy simulation to simulate high-Reynolds-number separated flows. The validation test case is a simplified space launcher afterbody with a control device in the form of a short cylindrical serrated skirt. "Zonal immersed boundary conditions" are used to handle the introduction of the skirt into the preexisting structured curvilinear grid that describes the noncontrolled configuration. The governing equations are solved using a standard body-fitted finite volume technique over the whole grid. A direct forcing source term is added when cells are internal to the skirt (that is, solid) to drive the velocity and the turbulence variables to the chosen values. Numerical simulations are performed at a Reynolds number of 1.2 × 10 6 and a freestream Mach number of 0.702. The numerical results demonstrate the ability of the zonal immersed boundary conditions to successfully impose the desired values at solid nodes. The first-and second-order moments, as well as the fluctuating pressure field, illustrate a fairly good agreement between the experiment and the numerical simulation. It is shown that the serrated skirt acts as a smooth device, which does not affect the global dynamics of the flow and only delays the location of the separation. Finally, the zonal immersed boundary conditions appear to successfully reproduce the effect of the skirt while drastically reducing the time of the grid generation.

A rapid and low noise switch from RANS to WMLES on curvilinear grids with compressible flow solvers

“…Then, the mimicking of the solid boundary is obtained for non-zero values of f ρu and f ρν whereas the continuity and energy equations remain unforced as in Mochel et al [64] and Weiss et al [121]. In particular, the term f ρ is kept equal to zero, which is an issue when the boundary is expected to strictly correspond to an adiabatic rigid wall changing the mass flow in a volume control surrounding the body modelled with IBC.…”

Towards the Prediction of Fluctuating Wall Quantities Using Immersed Boundary Conditions

“…The present method uses inside forcing points without wall models. This approach has been successfully used to reproduce the blockage effect of control devices on a space launcher afterbody by Mochel et al [25]. More recently, this approach was used by Weiss and Deck [5] on a pre-existing body-fitted simulation to add the geometrical details of a full space launcher geometry.…”

Cavitation Induction by Projectile Impacting on a Water Jet

“…Similar method has been used by Mochel et at. [9] in high velocity compressible turbulent flows as well as by Koukouvins et al [5] to simulate the cavitating flow resulting from the high-speed closure of the claw of the pistol shrimp. To the best of the authors' knowledge, apart from the method developed by Koukouvinis, the only IB methodology applied on cavitating flows, such as Diesel injector flows with closing needle, is presented by Orley et al [10], which consists of a cut cell methodology.…”