Forced-oscillation control of sound radiated from the flow around a cascade of flat plates

Tanaka, Yasutsugu; Yokoyama, Hiroshi; Iida, Akiyoshi

doi:10.1016/j.jsv.2018.06.013

Cited by 10 publications

(4 citation statements)

References 21 publications

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“…The coefficient, ϕ, which is defined as the porosity of the porous medium in the original VP method [34], was here determined as 0.25 considering the computational stability. It has been confirmed that the flow field around an oscillating plate was correctly predicted by the present methodologies [35].…”

Section: Governing Equations and Finite Difference Schemesupporting

confidence: 79%

Control of Flow around an Oscillating Plate for Lift Enhancement by Plasma Actuators

2019

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During insect flight, a feathering motion of the wing’s controls vortex shedding for lift enhancement. In this study, in order to control the flow around a wing flapping with simplified sinusoidal motion, plasma actuators were introduced to simplify the complex feathering motion. In a wind tunnel, a smoke-wire method was enacted to visualize the flow fields around an oscillating plate with an attack angle of 4° in a uniform flow for the baseline and controlled cases. The actuator placed around the leading edge was found to suppress the flow separation on the top surface. Numerical simulations were performed to investigate the control effects on the fluctuating lift, where the control effects by the intermittently driven actuator were also predicted. The actuator installed on the top surface throughout the up-stroke motion was found to suppress vortex shedding from the trailing edge, which resulted in an 11% lift enhancement compared to the baseline case. In regard to the effects of the installation position, it was found that the actuator placed on the top surface was effective, compared to the cases for installation on the bottom surface or both surfaces.

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Section: Governing Equations and Finite Difference Schemesupporting

confidence: 79%

Control of Flow around an Oscillating Plate for Lift Enhancement by Plasma Actuators

2019

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“…To reproduce the complex shape of the actual reed instrument and the oscillating reed on rectangular grids, the volume penalization method [30,31], one of the immersed- boundary methods [32], was utilized. The software for the simulation was developed by the authors [23,33,34]. In the previous study [34], the flow and acoustic fields around an oscillating cylinder and plates were correctly predicted.…”

Section: Governing Equations and Finite Difference Formulation For Computationsmentioning

confidence: 99%

“…The software for the simulation was developed by the authors [23,33,34]. In the previous study [34], the flow and acoustic fields around an oscillating cylinder and plates were correctly predicted.…”

Section: Governing Equations and Finite Difference Formulation For Computationsmentioning

confidence: 99%

Analysis of flow and acoustic radiation in reed instruments by compressible flow simulation

Yokoyama

Kobayashi

Iida

2020

Acoust. Sci. & Tech.

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Direct aeroacoustic simulations of flow and sound around an instrument with an oscillating reed were performed on the basis of compressible Navier-Stokes equations along with experiments with an artificial blowing device. The measured reed displacement was utilized as forced vibration in the computations. The predicted sound pressure spectrum shows that the level of the fundamental tone almost agrees with the measured result. The numerical results showed that the lowest acoustic mode of clarinet-type reed instruments (one-quarter wavelength mode) was reproduced. Moreover, the sound generation mechanism was discussed in detail using the predicted gradient of mass flow rate in the instrument. It was found that compression and expansion occur inside the mouthpiece, where the flow separation occurs after the spreading of the air jet from the reed channel exit along the inner wall of the mouthpiece. In addition, vortex ring shedding attributable to the acoustic particle velocity around the open end of the instrument was found to occur, causing an expansion wave from the instrument.

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“…The VP-based IBM for Navier-Stokes equations has been extensively applied to various aerodynamic problems including the flow simulation of porous trailing edge, 28 rotating fan, 29 moving/oscillating cascade 30 and moving cylinders. [31][32][33] For aeroacoustic applications such as the deformed slat noise simulation at high-Reynolds number by Kozubskaya et al, 34 the structured grids should be sufficiently fine in the vicinity of the solid boundaries to resolve the surface, and high-order schemes should be employed to minimise the numerical dissipation and dispersion.…”

Section: Introductionmentioning

confidence: 99%

Computational aeroacoustics of aerofoil leading edge noise using the volume penalization-based immersed boundary methods

Ying

Fattah

Cantos

et al. 2022

International Journal of Aeroacoustics

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Broadband noise due to the turbulence-aerofoil interaction, which is also called the leading edge noise, is one of the major noise sources of aircraft (including the engine). To study the noise properties numerically is a popular approach with the increasing power of computers. Conventional approaches of using body-fitted grids at the boundaries would be convoluted due to the complex geometries, which can constrain the efficiency of parametric studies. A promising approach to tackle this issue is to use the immersed boundary method (IBM). Among various IBM variants, the volume penalization (VP) approach employs a masking function to identify the immersed solid boundary, and continuous forcing terms are added to the original flow governing equations to account for the boundary conditions. It is, therefore, efficient and easy to implement into the existing computational aeroacoustics solvers. In this work, the VP-based IBM is used to simulate the leading edge noise by combining with the advanced synthetic turbulence method. The simulations are conducted for both the isolated aerofoils and cascade, and the results are compared with the well-validated body-fitted grid solutions. The viscosity effect is also highlighted by comparing the results obtained by solving both Euler and Navier–Stokes equations.

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Forced-oscillation control of sound radiated from the flow around a cascade of flat plates

Cited by 10 publications

References 21 publications

Control of Flow around an Oscillating Plate for Lift Enhancement by Plasma Actuators

Control of Flow around an Oscillating Plate for Lift Enhancement by Plasma Actuators

Analysis of flow and acoustic radiation in reed instruments by compressible flow simulation

Computational aeroacoustics of aerofoil leading edge noise using the volume penalization-based immersed boundary methods

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