Investigation on the Developing Turbulent Flow In a Curved Duct of Square Cross-Section Using a Low Reynolds Number Second Moment Turbulence Closure

2차모멘트 난류모형을 이용한 정사각 단면 곡덕트 내 발달하는 난류유동 변화에 대한 고찰

Fine grid calculations are reported for the developing turbulent flow in a curved duct of square cross-section with a radius of curvature to hydraulic diameter ratio ${\delta}=Rc/D_H=3.357 $ and a bend angle of 720 deg. A sequence of modeling refinements is introduced; the replacement of wall function by a fine mesh across the sublayer and a low Reynolds number algebraic second moment closure up to the near wall sublayer in which the non-linear return to isotropy model and the cubic-quasi-isotropy model for the pressure strain are adopted; and the introduction of a multiple source model for the exact dissipation rate equation. Each refinement is shown to lead to an appreciable improvement in the agreement between measurement and computation.