scholarly journals Aerodynamic performance of three-dimensional wing tip high Reynolds number turbulence with jet control

2021 ◽  
Vol 621 ◽  
pp. 012055
Author(s):  
Zizhen Huang ◽  
Chengyuan Luo ◽  
Peng Qian ◽  
Zhiwei Chen ◽  
Minghou Liu
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Three Dimensional ◽  
Aerodynamic Performance ◽  
Jet Control ◽  
High Reynolds ◽  
Wing Tip

Numerical Simulation of Flow around a Cylinder under Different Reynolds Number

2014 ◽  
Vol 543-547 ◽  
pp. 434-440
Author(s):  
Qiang Liu ◽  
Wei Xie ◽  
Wen Yang Duan ◽  
Chang Hong Hu
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Initial Field ◽  
Fine Grid ◽  
Flow Around A Cylinder ◽  
Wall Functions ◽  
High Reynolds ◽  
Les Model

Based on fully structured grids parallel numerical simulations of flow around a cylinder under different Reynolds number are carried out. Two-dimensional and three-dimensional models are established at the same time under specific Reynolds number, and further analyze of three-dimensional flow characteristics as well as the generated influence to overall physical quantities are presented. In order to explore efficient high Reynolds number turbulence models, a comparative research of the LES model without wall functions and the Spalart-Allmaras turbulence model is carried out. In order to improve the computational efficiency, a domain decomposition parallel computing strategy is used, and a calculation strategy that results of coarse grid was assigned to fine grid as initial field value by 3D linear interpolation is presented. Simulation results show that: Drag coefficient and Strouhal number have very good consistency with the experimental data, which verifies the correctness of the calculation method; Even if at low Reynolds number (200≤Re≤300), using a three-dimensional model is still necessary; While in the high Reynolds number stage, compared to LES model without wall functions, Spalart-Allmaras model is more applicable and more efficient.

Cellular vortex shedding in the wake of a tapered plate

2008 ◽  
Vol 617 ◽  
pp. 355-379 ◽  
Author(s):  
VAGESH D. NARASIMHAMURTHY ◽  
HELGE I. ANDERSSON ◽  
BJØRNAR PETTERSEN
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Vortex Shedding ◽  
High Reynolds Number ◽  
Three Dimensional ◽  
Base Pressure ◽  
Recirculation Bubble ◽  
Apparent Lack ◽  
Secondary Motion ◽  
High Reynolds

Direct numerical simulation (DNS) of vortex shedding behind a tapered plate with the taper ratio 20 placed normal to the inflow has been performed. The Reynolds numbers based on the uniform inflow velocity and the width of the plate at the wide and narrow ends were 1000 and 250, respectively. For the first time ever cellular vortex shedding was observed behind a tapered plate in a numerical experiment (DNS). Multiple cells of constant shedding frequency were found along the span of the plate. This is in contrast to apparent lack of cellular vortex shedding found in the high-Reynolds-number experiments by Gaster & Ponsford (Aero. J., vol. 88, 1984, p. 206). However, the present DNS data is in good qualitative agreement with similar high-Reynolds-number experimental data produced by Castro & Watson (Exp. Fluids, vol. 37, 2004, p. 159). It was observed that a tapered plate creates longer formation length coupled with higher base pressure as compared to non-tapered (i.e. uniform) plates. The three-dimensional recirculation bubble was nearly conical in shape. A significant base pressure reduction towards the narrow end of the plate, which results in a corresponding increase in Strouhal number, was noticed. This observation is consistent with the experimental data of Castro & Rogers (Exp. Fluids, vol. 33, 2002, p. 66). Pressure-driven spanwise secondary motion was observed, both in the front stagnation zone and also in the wake, thereby reflecting the three-dimensionality induced by the tapering.

scholarly journals On the boundary layer structure near a highly permeable porous interface

2016 ◽  
Vol 798 ◽  
pp. 88-139 ◽  
Author(s):  
Mohit P. Dalwadi ◽  
S. Jonathan Chapman ◽  
Sarah L. Waters ◽  
James M. Oliver
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Layer Structure ◽  
Three Dimensional ◽  
Interfacial Stress ◽  
Far Field ◽  
Dimensional Problem ◽  
Flow Through ◽  
High Reynolds ◽  
Porous Obstacle

The method of matched asymptotic expansions is used to study the canonical problem of steady laminar flow through a narrow two-dimensional channel blocked by a tight-fitting finite-length highly permeable porous obstacle. We investigate the behaviour of the local flow close to the interface between the single-phase and porous regions (governed by the incompressible Navier–Stokes and Darcy flow equations, respectively). We solve for the flow in these inner regions in the limits of low and high Reynolds number, facilitating an understanding of the nature of the transition from Poiseuille to plug to Poiseuille flow in each of these limits. Significant analytical progress is made in the high Reynolds number limit, and we explore in detail the rich boundary layer structure that occurs. We derive general results for the interfacial stress and for the conditions that couple the flow in the outer regions away from the interface. We consider the three-dimensional generalization to unsteady laminar flow through and around a tight-fitting highly permeable cylindrical porous obstacle within a Hele-Shaw cell. For the high Reynolds number limit, we give the coupling conditions and interfacial stress in terms of the outer flow variables, allowing information from a nonlinear three-dimensional problem to be obtained by solving a linear two-dimensional problem. Finally, we illustrate the utility of our analysis by considering the specific example of time-dependent forced far-field flow in a Hele-Shaw cell containing a porous cylinder with a circular cross-section. We determine the internal stress within the porous obstacle, which is key for tissue engineering applications, and the interfacial stress on the boundary of the porous obstacle, which has applications to biofilm erosion. In the high Reynolds number limit, we demonstrate that the fluid inertia can result in the cylinder experiencing a time-independent net force, even when the far-field forcing is periodic with zero mean.

A Calibration of a Feedwater Flowmeter Installed to Model Loop of a Nuclear Power Plant Using High Reynolds Number Facility

2008 ◽  
Author(s):  
Noriyuki Furuichi ◽  
Yoshiya Terao ◽  
Masaki Takamoto
Keyword(s):  
Reynolds Number ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
High Reynolds Number ◽  
Tube Bundle ◽  
Three Dimensional ◽  
Calibration Result ◽  
Calibration Facility ◽  
High Reynolds

A calibration result of ultrasonic flowmeters using in a feedwater flowrate in a nuclear power plant, is described under a variety of upstream conditions using the new high Reynolds number calibration facility. The pipe layouts are classified to five type three-dimensional one with two or three elbows. The flow conditioners are tube bundle type and Mitsubishi type. Pipe Reynolds number is up to 1.6×107. The large effect of the flow conditioner and pipe layout is observed for cramp-on type. For multi-path type, individuality is observed.

Numerical aerodynamic analysis of bluff bodies at a high Reynolds number with three-dimensional CFD modeling

2013 ◽  
Vol 56 (2) ◽  
pp. 277-289 ◽  
Author(s):  
YuGuang Bai ◽  
Kai Yang ◽  
DongKe Sun ◽  
YuGuang Zhang ◽  
David Kennedy ◽  
...  
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Three Dimensional ◽  
Cfd Modeling ◽  
Bluff Bodies ◽  
Aerodynamic Analysis ◽  
High Reynolds
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