In the present study, multiple-fan active control wind tunnel tests are conducted to investigate aerodynamic forces on a 5:1 rectangular cylinder in sinusoidal streamwise winds with different angles of attack (AoA). The effects frequency, amplitude, and AoA flow statistical parameters, spectral characteristics, spanwise distributions drag, lift, moment coefficients analyzed. Results show that e...

Submarine pipelines are appropriate method for transmission of oil and gas from sea bed. Free spans may occur due to the natural uneven seabed or by under-scouring. Vortex Induced Vibration (VIV) can happen in such free spans at high Reynolds number. Resonance occurs if the frequency of vortex shedding is close to the pipeline’s natural frequency leading to its fatigue that can break the pipeli...

The low frequency noise from heat recovery steam generator (HRSG) makes dominant contribution to the noise on the boundary of plant, which generation mechanism is investigated in this presentation. The non-stationary flow field and aeroacoustic noise is studied with hybrid numerical simulation, which is comprised of CFD method based on Large Eddy Simulation (LES) and acoustic analogy by using F...

A new method of the mode decomposition method developed by Huang et al. (1998) was applied to decompose the raw signal into a range of fluctuating components from high to low-frequencies in the study. Experimental results of base pressure signals were obtained at Re = 11760 and 31600, respectively. Results show that decomposition method is useful for further studying the low-frequency variation...

Testing of a 3D bluff body with and without end plate tabs was performed in the California Polytechnic State University 3x4 ft low speed wind tunnel. The CP values were obtained for the test case with no end plate tabs for speeds of 10, 15, 20, and 30 m/s. It was observed that stronger vortex shedding ocured at the higher speed test cases. The model was shimmed to be at approximately 5° angle o...

We develop a reduced-order model for large-scale unsteadiness (vortex shedding) in a two-dimensional diffuser and use the model to show how periodic mass injection near the separation point reduces stagnation pressure loss. The model estimates the characteristic frequency of vortex shedding and stagnation pressure loss by accounting for the accumulated circulation due to the vorticity flux into...

In the present study, we apply proportional (P), proportional-integral (PI) and proportional-differential (PD) feedback controls to flow over a circular cylinder at Re=60 and 100 for suppression of vortex shedding in the wake. The transverse velocity at a centreline location in the wake is measured and used for the feedback control. The actuation (blowing/suction) is provided to the flow at the...

The interaction between an initially laminar boundary layer developed spatially on a flat plate under the influence of vortex shedding induced from a rotating circular cylinder has been simulated numerically. The rotational speed of the cylinder is varied to generate the vortex shedding of different intensities. Also the flat plate is kept at different positions from the cylinder. Due to asymme...

A passive jet flow control method was employed to suppress the unsteady vortex shedding from a circular cylinder at the Reynolds number level of Re= (0.18~1.1)×10. The passive jet flow control was achieved by blowing jets from the holes near the rear stagnation point of the cylinder, which are connected to the in-take holes located near the front stagnation point through channels embedded insid...