Fluidic control of cavity configurations at transonic and supersonic speeds

Lada, C.; Kontis, Konstantinos

doi:10.1007/978-3-540-85181-3_76

Cited by 3 publications

(2 citation statements)

References 4 publications

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“…For cavities inside aircrafts utilized to store weapons, the maximum sound pressure level (SPL) can be 170dB [1], which damage components of aircrafts and disturb safety separation of storing weapons. Therefore, Many experimental and numerous investigations have been conducted over the past several decades to study cavity static and unsteady flow characteristics [2][3][4][5][6][7][8][9][10][11][12]. These results indicate that there were complex flow-field structure and aerodynamic noise characteristics inside cavities at transonic and supersonic flows.…”

Section: Introductionmentioning

confidence: 96%

Effects of boundary-layer thickness on aero-acoustics characteristics of subsonic shallow cavity flow

Yang

Liang

et al. 2012

2012 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)

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High-speed flows in cavities such as grooves, wheel wells, and weapon bays, are often encountered in aerospace and aeronautical vehicles. In most cases the flow field is complex and unsteady, featured by shear-layer instability, flow separation and formation of vortex structures, shock wave/boundary-layer interactions at transonic and supersonic speeds. Complex unsteady flow characteristics occur therein, such as fluctuating pressure and velocity. Some aerodynamic noise inside the cavity can reach 170dB, which can damage some installed apparatus inside the cavity and structural components of the cavity. Free-stream boundary layer has significant influence on aero-acoustic characteristics inside cavities. This paper presents that sound pressure level (SPL) distributions and sound pressure frequency spectrum (SPFS) characteristics at different measurement positions on cavity floor centerline utilizing two terms of experimental results under experimental conditions. Effects of different free-stream boundary-layer thickness to cavity depth ratios on shallow cavities (transitional and closed cavity flow) were discussed. The data presented herein was obtained about the cavities with length to depth ratios of 12 and 15 over a Mach number of 0.6 at a Reynolds number of 1.23×10 7 per meter. The results show that decrease in the boundary-layer thickness to the cavity depth ratios (δ/D) causes SPL amplification and noise enhancement at different measurement positions inside the cavities, especially the front and middle. Moreover, decrease in δ/D has a significant influence on SPFS characteristics and leads to increase in SPL in the frequency range of 0Hz＜f＜1000Hz at subsonic speeds (Ma=0.6). According to that above, decrease in the free-steam boundary layer has important effect on the aerodynamic noise, and it cause SPL amplification and noise enhancement, which has some bad effect on structural security of something in the cavities.

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Section: Introductionmentioning

confidence: 96%

Effects of boundary-layer thickness on aero-acoustics characteristics of subsonic shallow cavity flow

Yang

Liang

et al. 2012

2012 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA)

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“…In order to suppress the aerodynamic noise of open cavities, a large number of active and passive flow control studies have been carried out by domestic and foreign scholars [7][8] . Active control methods such as mass jet or boundary layer blowing [9][10] have limitations from the engineering application point of view because of the need to add additional devices and complex structure; in contrast, passive control has no auxiliary energy consumption, easy application, more reliable performance and strong engineering practicality.…”

Section: Introductionmentioning

confidence: 99%

Effect of rear wall inclination on cavity acoustic characteristics at high Mach numbers

Tang

Luo

Zhang

et al. 2022

J. Phys.: Conf. Ser.

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Cavity flow has been a research hotspot in aerodynamics. Cavities with low Mach numbers have been extensively investigated, while those with high Mach numbers have been less explored. In this study, a flow control method specific to the acoustic characteristics of an open-type cavity with a high Mach number was studied through the improved delayed detached eddy simulation (IDDES). Next, the rear wall of the cavity was inclined to mitigate the impact strength formed by the airflow on the rear wall surface, thus reaching the goal of reducing the aerodynamic noise in the cavity. The Mach number and length-to-depth ratio of the cavity were calculated as 3.51 and 4.5, respectively. The calculation results manifested that under a high Mach number, the sound pressure level (SPL) at the bottom of the cavity and that at its front wall surface could be obviously reduced by inclining the rear wall, and the reduction amplitude increased with the increase in the inclination angle. At the inclination angle of 60°, the SPL at the bottom could be reduced by 24 dB at maximum.

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Effects of wall temperature on separation structures in supersonic flow over a semi-circular cavity

et al. 2022

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The influence of wall temperature on the vortex structure and flow characteristics of flow in semi-circular cavities is numerically investigated in this paper. The results show that the separation and reattachment points move downstream, and the secondary vortex increases with increases in wall temperature. In the secondary vortex section, normalized wall shear stress in the polar map has good consistency at different wall temperatures, and the flow properties of the three extreme points on the map are similar to Couette flow. In addition, the secondary vortex region can be regarded as an isobaric high-pressure region, while the pressure gradients slowly vary as the wall temperature increases. We confirm the independence of separation pressure for the wall temperature using pressure distribution and find that the peak and inflection points are at the reattachment points and separation points, respectively. Moreover, using a series of numerical calculations of the positions of the vortex center at different wall temperatures, explicit empirical formulas for estimating the positions of the primary vortex center are put forward. Using a topological mapping method, cavity flow is converted into quasi-one-dimensional steady-state compressible viscous flow through a variable cross-section pipe, and the flow parameter distribution, including the Mach number and pressure, conforms to the rule of quasi-one-dimensional flow.

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Fluidic control of cavity configurations at transonic and supersonic speeds

Cited by 3 publications

References 4 publications

Effects of boundary-layer thickness on aero-acoustics characteristics of subsonic shallow cavity flow

Effects of boundary-layer thickness on aero-acoustics characteristics of subsonic shallow cavity flow

Effect of rear wall inclination on cavity acoustic characteristics at high Mach numbers

Effects of wall temperature on separation structures in supersonic flow over a semi-circular cavity

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