Successes and Challenges for Flow Control Simulations

Rumsey, Christopher L.

doi:10.1260/1756-8250.1.1.1

Cited by 34 publications

(15 citation statements)

References 56 publications

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“…Cui & Agarwal (2006) also performed 3-D simulations and included slot ends but showed limited agreement with the experiments, possibly because the grid used was fairly coarse with only 29 points along the spanwise length of the slit (note that the aspect ratio of the slit is 28). For a detailed survey of simulations for this case, see Rumsey (2009). Amitay & Cannelle (2006) also carried out detailed experimental measurements for finite-span synthetic jets (i.e.…”

Section: Synthetic Jets In Quiescent Conditionsmentioning

confidence: 99%

Three-dimensional interactions between a finite-span synthetic jet and a crossflow

et al. 2011

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A complementary experimental and numerical investigation was performed to study the three-dimensional flow structures and interactions of a finite-span synthetic jet in a crossflow at a chord-based Reynolds number of 100 000 and a 0 • angle of attack. Six blowing ratios in the range of 0.2-1.2 were considered. Experiments were conducted on a finite wing with a cross-sectional profile of NACA 4421, where particle-image velocimetry data were collected at the centre jet. To complement the experiments, three-dimensional numerical simulations were performed, where the numerical set-up matched not only the physical parameters (e.g. free stream) but also the physical dimensions (e.g. orientation and location of the jet. For the low blowing ratio cases, spatial non-uniformities developed, due to the finite span of the slit, which led to the formation of small and organized secondary structures or a streak-like pattern in the mean flow. On the other hand, for the high blowing ratio range, turbulent vortical structures were dominant, leading to larger spanwise structures, with a larger spanwise wavelength. Moreover, the phase-locked flow fields exhibited a train of counter-rotating coherent vortices that lifted off the surface as they advected downstream. In the mid-blowing ratio range, combined features of the low range (near the slit) and high range (in downstream locations) were found, where a pair of counter-rotating vortices issued in the same jet cycle collided with each other. In all cases, the spanwise extent of the secondary coherent structures reduced with downstream distance with a larger decrease at higher blowing ratios. Similar observations were made in earlier studies on finite-span synthetic jets in quiescent conditions.

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Section: Synthetic Jets In Quiescent Conditionsmentioning

confidence: 99%

Three-dimensional interactions between a finite-span synthetic jet and a crossflow

et al. 2011

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“…Cui & Agarwal (2006) also performed 3-D simulations and included slot ends but showed limited agreement with the experiments which is possibly because the grid used was fairly coarse with only 29 points along the spanwise length of the slit (note that the aspect ratio of the slit is 28). For a detailed survey of simulations for this case see Rumsey (2009). Amitay & Cannelle (2006) also carried out detailed experimental measurements for finite-span synthetic jets (i.e., issued via rectangular slits) in quiescent conditions, where they collected PIV data on two planes across and along the slit.…”

Section: I1 Synthetic Jets In Quiescent Conditionsmentioning

confidence: 99%

“…Three-dimensional simulations showed a reasonable qualitative agreement with experiments (e.g., see Xia & Qin, 2005;Cui & Agarwal, 2005;Dandois et. al., 2006); for a survey of numerical simulations for this case see Rumsey (2009).…”

Section: I2 Low Aspect Ratio Synthetic Jets In a Cross-flowmentioning

confidence: 99%

Fundamental Experimental and Numerical Investigation of Active Control of 3-D Flows

Amitary¹,

Jansen²

2011

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A complementary experimental and numerical investigation was performed to study the 3-D flow structures and interactions of finite-span synthetic jets in a cross-flow at a chord-based Reynolds number range from 50,000 to 400,000 and angles of attack between 0 0 to 20 0 . A range of momentum coefficients was considered corresponding to six different blowing ratios in the range of 0.2 to 1.2 with an increment of 0.2 (where, the blowing ratio is defined based on the averaged outstroke jet velocity to the free-stream velocity). Experiments were conducted on two finite wings (unswept and 30 0 swept-back configurations) with a cross-sectional profile of NACA 4421, where both 2-D and stereoscopic PIV data were collected at various spanwise locations along the wing. In complement to the experiments, 3-D numerical simulations were performed, where the numerical setup not only matched the physical parameters (e.g., free-stream, blowing ratio, etc.) but also the physical dimensions (e.g., orientation and location of jet, flow control cavity including slot and chamber, etc.). Note that the numerical simulations only address one topic, which is the interaction of a single synthetic jet with a cross-flow over the unswept wing configuration, whereas the experiments included three sets of data: (1) a single finite span synthetic jet interacting with a finite unswept wing, (2) a single finite span synthetic jet interacting with a finite sweptback wing, and (3) multiple finite span synthetic jets interacting with a finite unswept wing.I.

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“…Rumsey summarized in 2008 that there had not been many published results for computation of synthetic jet in a cross flow since the CFD workshop organized by NASA in 2004 [26]. Therefore, Work reported in this paper aimed to develop a three-dimensional LES model which was reasonably capable of simulating the laminar separation bubble caused by adverse pressure gradient, to provide a numerical baseline flow required for predicting the effectiveness of a synthetic jet actuator (SJA) in controlling boundary layer flow separation.…”

Section: Introductionmentioning

confidence: 99%

LES of synthetic jets in boundary layer with laminar separation caused by adverse pressure gradient

2010

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In the development of synthetic jet actuators (SJAs) for active flow control, numerical simulation has played an important role. In controlling the boundary layer flow separation, an integrated numerical model which includes both the baseline flow and the SJA is still in its initial stage of development. This paper reports preliminary results of simulating the interaction between a synthetic jet and a laminar separation bubble caused by adverse pressure gradient in a boundary layer. The computational domain was three-dimensional and Large-eddy simulation (LES) was adopted. The initial and boundary conditions were defined using or referring to our wind tunnel experimental results. Prior to numerically simulating the interaction between the synthetic jets and the baseline flow, a numerical model for simulating the separation bubble was developed and verified. In the numerical model including the SJA, the synthetic jet velocity at the exit of the SJA was defined as an input. The numerical model was further verified by comparing the simulation with experimental results. Based on reasonable agreement between the numerical and experimental results, simulations were carried out to investigate the dependency of flow control using synthetic jets on the forcing frequency, focused on the lower frequency range of the Tollmien-Schlichting (T-S) instability, and on the forcing amplitude which was represented by the maximum jet velocity at the exit of the SJA. Supporting the hypothesis based on the 1 experiment, LES results showed that the forcing frequency had stronger influence on SJA's effective elimination of the separation bubble than the forcing amplitude did.Key words: synthetic jet actuator, micro sensor, numerical modeling, flow control.

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Successes and Challenges for Flow Control Simulations

Cited by 34 publications

References 56 publications

Three-dimensional interactions between a finite-span synthetic jet and a crossflow

Three-dimensional interactions between a finite-span synthetic jet and a crossflow

Fundamental Experimental and Numerical Investigation of Active Control of 3-D Flows

LES of synthetic jets in boundary layer with laminar separation caused by adverse pressure gradient

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