서지주요정보
Numerical study of laminar near-wake vortices behind a circular cylinder = 원주의 층류 근접 후류 와동에 관한 수치적 연구
서명 / 저자 Numerical study of laminar near-wake vortices behind a circular cylinder = 원주의 층류 근접 후류 와동에 관한 수치적 연구 / Jong-Youb Sa.
저자명 Sa, Jong-Youb ; 사종엽
발행사항 [서울 : 한국과학기술원, 1989].
Online Access 원문보기 원문인쇄

소장정보

등록번호

4105418

소장위치/청구기호

학술문화관(문화관) 보존서고

DAE 8902

SMS전송

도서상태

이용가능

대출가능

반납예정일

초록정보

The unsteady incompressible Navier-Stokes equations are solved for the laminar flow past a circular cylinder in the Reynolds number range 50-200 to investigate the behavior of the vortices in the near-wake. The Euler explicit finite difference scheme is used for the vorticity equation and the direct elliptic solver (SEVP) for the stream function equation. An integral-series method is newly developed for accurate evaluation of the stream function on the far boundary of a finite two-dimensional flow domain. For the stationary cylinder, present results indicate that the so-called Berger's 'low-speed mode' and 'basic mode' in the Strouhal number-Reynolds number relation are the same thing when the turbulence effect is absolutely eliminated from the vortex phenomenon. The two different shedding mechanisms experimentally observed, the wake instability and the direct voirtex shedding, are also numerically obtained in the present study with their inter-transition Reynolds number at about 80. For the heated or cooled cylinder, purely periodic flows at Re=100 was found to degenerate abruptly into a steady twin vortices at the critical Grashof number 1500, confirming an earlier experimental observation identified by the name 'breakdown of the Karman vortex street.' Various other buoyancy effects associated with the heating or cooling of the cylinder have been discussed in terms of flow patterns, Nusselt number and drag coefficient. For the oscillated cylinder, the phenomenon of so-called 'lock-is' in examined. The change of amplitude and frequency causes the vortex shedding pattern to have dual types. The generation of secondary vortices has been investigated in detail in the lock-in range.

서지기타정보

서지기타정보
청구기호 {DAE 8902
형태사항 [iii], 128 p. : 삽도 ; 26 cm
언어 영어
일반주기 Includes appendix
저자명의 한글표기 : 사종엽
지도교수의 영문표기 : Keun-Shik Chang
지도교수의 한글표기 : 장근식
학위논문 학위논문(박사) - 한국과학기술원 : 기계공학과,
서지주기 Reference : p. 63-71
주제 Vortex-motion.
Finite differences.
Unsteady flow (Fluid dynamics)
Wakes (Fluid dynamics)
소용돌이. --과학기술용어시소러스
층류. --과학기술용어시소러스
후류. --과학기술용어시소러스
유한 차분법. --과학기술용어시소러스
비압축성 흐름. --과학기술용어시소러스
Laminar flow.
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