Effect of wing placement on transition, boundary layer displacement thickness and broadband noise날개 형상이 천이, 경계층 배제두께 광역소음에 미치는 영향에 대한 연구

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The effect of wing sweep on the transition, boundary layer displacement thickness and turbulent boundary layer trailing edge noise (TBL-TE) has been numerically investigated by using empirical airfoil self-noise model and CFD calculations. In present work, boundary layer change due to sweep effect is mainly concerned which could influence the TBL-TE noise. Transition effect is found out to be essential in boundary layer calculation. The Michel transition model is employed in current work and verified in several 2D and 3D cases; the influences of T-S wave and cross-flow instability for triggering transition are discussed. FLUENT as the CFD calculation tool in current study is validated and by using User Defined Function (UDF) the 2D and 3D information of transition location is imposed into FLUENT due to the lack of transitional model in itself. Additionally, the acoustic treatment of sweep effect is used for broadband noise calculation based on Ffowcs Williams and Hall’s theory. As the investigation of the infinite swept wing at low angle of attack, the sweep effects are conducted in several aspects: pressure coefficient, transition location, velocity profiles in boundary layer, boundary layer displacement thickness and TBL-TE broadband noise. The results show that the sweep effect on the reduction of boundary layer displacement thickness is small compared with straight blade, which means the change of boundary layer does not contribute much to the TBL-TE noise. Final prediction of broadband noise is done and the result shows small reduction due to the boundary layer change, however, the acoustic correction of sweep effect should be considered which contributes about 2.3 dB reductions for broadband noise. At last the sweep effect in infinite zigzag wing was conducted to check the effect of sweep forward and sweep backward on transition and boundary layer displacement thickness.
Advisors
Lee, Duck-Jooresearcher이덕주researcher
Description
한국과학기술원 : 항공우주공학전공,
Publisher
한국과학기술원
Issue Date
2008
Identifier
297270/325007  / 020064303
Language
eng
Description

학위논문(석사) - 한국과학기술원 : 항공우주공학전공, 2008.2, [ vi, 63 p. ]

Keywords

boundary layer; transition; sweep; broadband noise; 경계층; 천이; 후퇴각; 광역소음; boundary layer; transition; sweep; broadband noise; 경계층; 천이; 후퇴각; 광역소음

URI
http://hdl.handle.net/10203/27016
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=297270&flag=dissertation
Appears in Collection
AE-Theses_Master(석사논문)
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