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In this study a numerical code for the simulation of turbulent channel flows with non-planar moving walls is presented. The solid boundaries of the chan- nel are immersed within the frame of a fixed non-body-conformal Cartesian grid. Spatial discretization of the incompressible Navier-Stokes equations (in primitive variables) is performed using second-order accurate finite dif- ferences. A three-step Runge-Kutta method is applied in conjunction with a fractional step technique for time advancement. The key novelty of the numerical technique lies in an innovative implementation of the Immersed Boundary Method (IBM). No-slip boundary conditions on immersed solid walls are enforced through an interpolation-free procedure applied to the discrete momentum equation.
The ability of the flow solver to resolve a complex turbulent channel flow in the presence of moving walls is tested by simulating a peristaltic actuator for turbulent skin-friction drag reduction. In accordance with existing results, a downstream traveling peristaltic wave of wall deformation is proved to allow for large drag reduction rates. Further, under some sets of parameters, a full relaminarization of the flow is observed.