• 제목/요약/키워드: Turbulent hypersonic flows

검색결과 5건 처리시간 0.018초

Hypersonic 뭉뚝 물체 흐름에 적용된 CFD (Computational Fluid Dynamics Applied to Hypersonic Blunt Body Flows)

  • 백두성;한영출;하영민;김득상
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2001년도 춘계학술대회논문집E
    • /
    • pp.311-316
    • /
    • 2001
  • The thin-layer Navier-Stokes equations are solved for the hypersonic flow over blunt cone configurations with applications to laminar as well as turbulent flows. The equations are expressed in the forms of flux-vector splitting and explicit algorithm. The upwind schemes of Steger-Warming and van Leer are investigated in their ability to accurately predict the heating loads along the surface of the body. A comparison with the second order extensions of these schemes is made and a hybrid scheme incorporating a combination of central differencing and flux-vector-splitting is presented. This scheme is also investigated in its ability to accurately predict heat transfer distributions.

  • PDF

뭉뚝한 물체 주변에 형성된 극초음속유동해석 (Analytical Solution for Hypersonic Flow on Blunt Bodies)

  • 백두성
    • 한국전산유체공학회지
    • /
    • 제8권4호
    • /
    • pp.1-5
    • /
    • 2003
  • A Thin-layer Wavier-Stokes equations are applied for the hypersonic flow over blunt bodies with applications to laminar as well as turbulent flows. The equations are expressed in the forms of flux-vector splitting and explicit algorithm. The upwind schemes of Steger-Warming and Van Leer are investigated to predict accurately the heating loads along the surface of the body. A mixed scheme has been presented for the differencing the convective terms and the mixed scheme is found to be less dissipative producing accurate solutions.

뭉뚝물체 주변에 형성된 극초음속유동에 대한 Navier-Stokes 계산 (Navier-Stokes Computations for Hypersonic flow on Blunt Bodies)

  • 백두성;김득상
    • 한국전산유체공학회:학술대회논문집
    • /
    • 한국전산유체공학회 2001년도 추계 학술대회논문집
    • /
    • pp.91-97
    • /
    • 2001
  • The thin-layer Navier-Stokes equations are solved for the hypersonic flow over blunt cone configurations with applications to laminar as well as turbulent flows. The equations are expressed in the forms of flux-vector splitting and explicit algorithm. The upwind schemes of Steger-Warming and van Leer are investigated in their ability to accurately predict the heating loads along the surface of the body. A comparison with the second order extensions of these schemes is made and a hybrid scheme incorporating a combination of central differencing and flux-vector-splitting is presented. This scheme is also investigated in its ability to accurately predict heat transfer distributions.

  • PDF

A New Convergence Acceleration Technique for Scramjet Flowfields

  • Bernard Parent;Jeung, In-Seuck
    • 한국추진공학회:학술대회논문집
    • /
    • 한국추진공학회 2004년도 제22회 춘계학술대회논문집
    • /
    • pp.15-25
    • /
    • 2004
  • This paper outlines a new convergence acceleration de-signed to solve scramjet flowfields with zones of re-circulation. Named the “marching-window”, the algorithm consists of performing pseudo-time iterations on a minimal width subdomain composed of a sequence of cross-stream planes of nodes. The upstream boundary of the subdomain is positioned such that all nodes upstream exhibit a residual smaller than the user-specified convergence threshold. The advancement of the downstream boundary follows the advancement of the upstream boundary, except in zones of significant streamwise ellipticity where a streamwise ellipticity sensor ensures its continuous progress. Compared to the standard pseudo-time marching approach, the march-ing-window is here seen to decrease the work required for convergence by up to 24 times for supersonic flows with little streamwise ellipticity and by up to 8 times for supersonic flows with large streamwise separated regions. The memory requirements are observed to be reduced sixfold by not allocating memory to the nodes not included in the computational subdomain. The marching-window satisfies the same convergence criterion as the standard pseudo-time stepping methods, hence resulting in the same converged solution within the tolerance of the user-specified convergence threshold. The extension of the marching-window to the weakly-ionized Navier-Stokes equations is also discussed.

  • PDF

Heat Transfer Analysis for Endothermic Reacting Fluids

  • Kimura, Hiroyuki
    • 한국추진공학회:학술대회논문집
    • /
    • 한국추진공학회 2008년 영문 학술대회
    • /
    • pp.346-357
    • /
    • 2008
  • Endothermic fuels are known as a probable fuel for hypersonic atmospheric flight vehicles and advanced propulsion systems, as well as cryogenic fuels. Especially, from the standpoint of the advanced regenerative cooling use, they are quite useful as a coolant fuel because of their large heat sink due to their chemical decompositions; so-called endothermic cooling effect. However, no heat transfer equations have been proposed taking into account such endothermic reactive behaviors concretely. This paper describes an analytical method for evaluation of the heat transfer rates between endothermic reacting coolant fuel and coolant-side wall in the regenerative cooling passages. Heat transfer mechanism is indicated based on a classical transport-phenomenological approach. A new relational expression of Nusselt number ratio for forcedconvective heat transfer with such endothermic reactions is also proposed by theoretical approaches using some classical hypotheses. Its applicability is assessed provisionally by comparison with confirmed results of heated tube tests for supercritical JP-7 fuel carried out at NASA Lewis Research Center, using its heat sink characteristics evaluated by United Technologies Research Center(UTRC). As a result, it has been suggested that the proposed relational equation is applicable to the evaluation of enhancement of Nusselt numbers due to such reactions in developed turbulent flows such as in the regenerative cooling passages.

  • PDF