This paper presents high-fidelity simulations of the Vortex-Induced Vibration (VIV) phenomena using a new computational model based on the high-order spectral difference (SD) method on unstructured grids. The SD method has shown promise in the past as a highly accurate, yet sufficiently fast method for solving unsteady viscous compressible flows. A Riemann solver is used to compute the inviscid fluxes at the cell interfaces, and the viscous fluxes are computed using an averaging mechanism based on the fluxes from the two cells that share the interface. A third-order Runge-Kutta scheme is used to advance time. In this viscous, compressible flow solver, the displacement of an elastically mounted bluff body has been coupled to the lift force created by vortex shedding. The solver is validated by correlating the lift and drag coefficients with previous published results of two cases: single rigid cylinder, and single elastically mounted cylinder. The rigid cylinder case validates the accuracy of the fluid solver. The elastically mounted case validates the fluid-structure coupling. We simulate the phenomenon of wake galloping with two cylinders after the solver has been validated using single cylinder VIV phenomenon.
A computational study is conducted to compare the performance of an array of steady jets and sweeping jets (generated by fluidic oscillator) interacting with an attached turbulent cross flow. Both jets operate at the same supply rate and with the jet-to-freestream velocity ratio of three. Two array spacings are considered in this study; one is chosen based on the minimum possible distance between the adjacent fluidic oscillators, and the other spacing represents an actuator’s configuration with the least interaction between jets. The improved delayed detached eddy simulation model is employed as a high fidelity turbulence modeling approach to resolve accurately the flow structures. Formation of strong vortex pairs is observed in both actuation techniques with the opposite sense of rotation between them. As expected, the sweeping jet affects a wider region of incoming turbulent flow along the spanwise direction compared to the steady jet. Examining the turbulence properties of the flow downstream of the jets indicates that the sweeping jet is a better candidate for enhancing the mixing mechanism used to control separation. Comparing both the instantaneous and time-averaged flow fields generated by the sweeping jets and steady jets reveals that the interaction between the adjacent sweeping jets at the minimum spacing arrangement is significantly stronger than that of the steady jets.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.