Experimental Study on Aerodynamic Noise Generated from Two-Dimensional Models. 1st Report. Study on Wind Tunnel Wall Effect and Wall Materials.

肇, 藤田; 純一, 白石; 健, 栗田; 芳幸, 丸田; 彰二, 山田

doi:10.1299/kikaib.62.187

Cited by 9 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(5) The downstream NACA airfoil contributes most greatly into the increase of OASPL at L>L c as the sound source of DFN.…”

Section: Discussionmentioning

confidence: 98%

“…2 shows the schematic diagram of experimental setup for the acoustic measurement. The endplates [5] of acoustic permeability material are installed in order to avoid the interference between large scale turbulence generated in the jet edge and the models. For the coordinate system, the leading edge of airfoil and the center of airfoil span is defined as the origin, and x, y, z axes show streamwise, horizontal and vertical directions, respectively.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An experimental study on aerodynamic sound generated from wake interference of circular cylinder and airfoil vane in tandem

et al. 2006

View full text Add to dashboard Cite

The purpose of this study is to investigate the characteristics of aerodynamic sound generated from wake interference of circular cylinder and airfoil vane located in tandem and to clarify the generation mechanism of the sound source with discrete frequency. The effects of the interval between the cylinder and the airfoil on the characteristics of aerodynamic sound are investigated by acoustic measurement, flow visualization and exploration test of sound source. The relation between the flow field and the sound field with discrete frequency noise (DFN) is shown, and then it is found that the downstream airfoil works as the sound source of DFN, which has the frequency of vortex shedding from the upstream cylinder, when the interval of two bodies is longer than a critical distance.

show abstract

“…(5) The downstream NACA airfoil contributes most greatly into the increase of OASPL at L>L c as the sound source of DFN.…”

Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

An experimental study on aerodynamic sound generated from wake interference of circular cylinder and airfoil vane in tandem

et al. 2006

View full text Add to dashboard Cite

show abstract

“…The wind tunnel with a circuit and semi-open type, has an open test section of 0.3 m × 0.3 m. The flow noise level is less than 55 dB (A) and the turbulence level is less than 0.2 % at a velocity of 40 m/s. The endplates were installed in the test section because in an open type wind tunnel, interference between the large scale turbulence in the jet edge and the model generates unexpected additional aerodynamic noise and destroys the two-dimensionality of the flow around the model (Fujita et al, 1996). The circular cylinder was set up as shown in Fig.…”

Section: Experiments Using Low Noise Wind Tunnelmentioning

confidence: 99%

Visualization of three-dimensional flow structures in the wake of an inclined circular cylinder

Matsuzaki

Shingai

Haramoto

et al. 2004

J Vis

View full text Add to dashboard Cite

In the previous measurements of the aerodynamic sound generated from an inclined circular cylinder, it is reported that the sound pressure level (SPL) changes with the aspect ratio and the inclined angle. Therefore, we have investigated the changes in the vortex structure of the wake considered as one of the causes of the SPL variation. Using the low-noise wind tunnel, the velocity fluctuation in the wake is measured to obtain the correlation length. Moreover, the flow visualization is performed with a hydrogen bubble method and a numerical analysis method in order to clarify how the wake structure changes by variations of aspect ratio and inclined angle. As a result of this investigation, it is shown that the spanwise structure of Karman's vortex is highly influenced by the interference of Karman's vortex with the bottom endplate, and that the influence on the spanwise structure in the wake becomes greater as the aspect ratio decreases and the inclined angle increases.

show abstract

“…at ~ =20 ° is smaller than one at ~u--0 °. (1)(2)(3) In the case of A=10, the compensated Strouhal number at ~ = 20 ° is smaller than one at ~u =0O, particularly near the bottom of the cylinder.…”

Section: Discussionmentioning

confidence: 94%

Relation between the three-dimensional flow structure and aerodynamic sound generated from inclined circular cylinder

et al. 2004

View full text Add to dashboard Cite

The major causes of the sound pressure level (SPL) variation due to the changes of the inclined angle of a circular cylinder and the aspect ratio (ratio of distance between endplates to cylinder diameter) were investigated. The velocity fluctuation of the wake and the surface pressure fluctuati6n of the cylinder were measured in a low noise wind tunnel to fred the correlation length, coherent output power and Strouhal number. The results show that the changes of these values qualitatively correspond with the change of SPL. Flow visualization tests are performed to clarify the variation of wake in relation with inclined angle and aspect ratio. It is found that the spanwise structure of Karman's vortex street is broken down by the upward flows generated around the bottom endplate, and the degree of the interference between the upward flow and Karman's vortex street is smaller when the aspect ratio is larger.

show abstract

Experimental Study on Aerodynamic Noise Generated from Two-Dimensional Models. 1st Report. Study on Wind Tunnel Wall Effect and Wall Materials.

Cited by 9 publications

References 0 publications

An experimental study on aerodynamic sound generated from wake interference of circular cylinder and airfoil vane in tandem

An experimental study on aerodynamic sound generated from wake interference of circular cylinder and airfoil vane in tandem

Visualization of three-dimensional flow structures in the wake of an inclined circular cylinder

Relation between the three-dimensional flow structure and aerodynamic sound generated from inclined circular cylinder

Contact Info

Product

Resources

About