Experimental Study of Steady Blowing from the Trailing Edge of an Open Cavity Flow
Cavity flows have a wide range of low-speed applications (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>M</mi><mo>≤</mo><mn>0.3</mn></mrow></semantics>...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Aerospace |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2226-4310/12/1/7 |
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| Summary: | Cavity flows have a wide range of low-speed applications (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>M</mi><mo>≤</mo><mn>0.3</mn></mrow></semantics></math></inline-formula>), such as aircraft wheel wells, ground transportations, and pipelines. They induce strong flow oscillations which can substantially increase noise, drag, vibration, and lead to structural fatigue. In the current study, a steady jet was forced from the cavity trailing edge with different momentum fluxes (<i>J</i> = 0.11 kg/m·s<sup>2</sup>, 0.44 kg/m·s<sup>2</sup>, and 0.96 kg/m·s<sup>2</sup>). The aim of this study was to investigate the impact of the steady jet on the time-averaged flow field and the cavity separated shear layer oscillations for an open cavity with a length-to-depth ratio of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>L</mi><mo>/</mo><mi>D</mi><mo>=</mo><mn>4</mn></mrow></semantics></math></inline-formula> at <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>R</mi><msub><mi>e</mi><mi>θ</mi></msub><mo>=</mo><mn>1.28</mn><mo>×</mo><msup><mn>10</mn><mn>3</mn></msup></mrow></semantics></math></inline-formula>. Particle image velocimetry, surface oil flow visualisation, constant temperature anemometry, and pressure measurements were performed. The study found that increasing the jet momentum flux caused a significant increase in thickness and deflection of the cavity separated shear layer. Due to the counterflow interaction between the jet and cavity separated shear layer, the growth rate (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>d</mi><msub><mi>δ</mi><mi>ω</mi></msub><mo>/</mo><mi>d</mi><mi>x</mi></mrow></semantics></math></inline-formula>) of the cavity separated shear layer increased significantly from 0.193 for the no-jet case to 0.273 for the <i>J</i> = 0.96 kg/m·s<sup>2</sup> case. As a result, the return flow rate increased, causing the separation point on the cavity floor to shift upstream from <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>x</mi><mo>/</mo><mi>L</mi><mo>≈</mo><mn>0.2</mn></mrow></semantics></math></inline-formula> for the no-jet case to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>x</mi><mo>/</mo><mi>L</mi><mo>≈</mo><mn>0.1</mn></mrow></semantics></math></inline-formula> for the <i>J</i> = 0.96 kg/m·s<sup>2</sup> case. Furthermore, increasing the jet momentum flux increased the broadband level of the cavity separated shear layer oscillations. |
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| ISSN: | 2226-4310 |