Numerical simulation and experiments on turbulent air flow around the semi-circular profile at zero angle of attack and moderate Reynolds number

Abstract

Two-dimensional flow around a semi-circular profile at the zero angle of attack and at Re = 50000 on the self-oscillatory period is extensively studied by the URANS method involving the standard semi-empirical SST turbulence models, the SST turbulence model with the correction for streamline curvature modified within the Rodi-Leschziner-Isaev and Smirnov-Menter approaches, as well as involving Hanjalic's four-parameter eddy viscosity elliptic relaxation model and its analog-eddy viscosity elliptic blending model proposed in the present work. This has been done with the use of different-structure grids (multiblock with structured overlapping and unstructured composite). Different numerical approximation methods realized in six codes (VP2/3, SigmaFlow, Fluent, CFX, OpenFOAM, and StarCCM+) are used. An underestimation (up to 30%) of time-averaged integral aerodynamic loads is revealed by means of the standard near-wall SST model. This is explained by the high vortex viscosity production in the profile wake. Wind tunnel tests show that the location of cutoff washers on the semi-circular profile provides a quasi-two-dimensional flow around it and allows applying measurement data to verify two-dimensional turbulent flow. The best agreement of experimental results and numerical predictions when comparing the Strouhal number and time-averaged surface pressure coefficient distributions is achieved using both the modified SST model with the correction for streamline curvature and the modified eddy viscosity elliptic blending model. When the SST model with the correction for streamline curvature, modified within the Rodi-Leschziner-Isaev, Smirnov-Menter and Durbin approaches, is used, all the above codes yield close predictions of a vertical aerodynamic load on the oscillation period.

Large-eddy simulations of the flow over a semi-circular cylinder at Re = 50000

“…From the numerical modeling point of view, it is interesting to compare the present LES results to calculations reported by Isaev et al [8], [13], who have teresting finding of the present study. It is worth noting that Isaev et al [8], [13] reported a bi-modal distribution of the drag force as well, which could support the present findings.…”

“…The differences between the present LES, available URANS [8], [13] and experimental results were discussed [7], [8]. Furthermore, we provided a detailed analysis and comparison of the available numerical (LES and direct numerical simulations, DNS) and experimental data for the flows past CC ( [14], [15], [16], [17], [18], [4], [19] ) and SC ( [20], [21], [22], [23], [9], [24], [11], [25]) to compensate the limitation of HC experimental data to the integral flow parameters only.…”

Моделирование Влияния Сдвига Ветра На Снижение Лобового Сопротивления Энергоэффективного Высотного Сооружения С Использованием Дросселирующего Эффекта

“…Описанный обобщенный подход Роди-Лешцинера-Исаева (RLI) [19] позволяет избежать нефизической накачки вихревой вязкости. Поправка на кривизну линий тока в рамках подхода RLI введена в пакеты VP2/3 (Velocity-Pressure, 2D/3D) и sigma-flow [12,20].…”

Standard and Modified SST Models with the Consideration of the Streamline Curvature for Separated Flow Calculation in a Narrow Channel with a Conical Dimple on the Heated Wall

“…Approving and testing the RLI approach when comparing the numerical predictions obtained by different semi-empirical models and software with the experimental data were made to solve the traditional tasks of recirculating the flows, as well as of the flow and heat transfer control due to forming intense large-scale vortex structures [58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77]. The first group of tasks included recirculating flows in a square cavity with a movable cover [53] in a round cavity on the wall of the plane-parallel [53,58] and U-shaped [59,60,78] channels for the periodic flow around the airfoil NACA0012 when the angle of attack was varied from 0 • to 180 • [61].…”

“…The cycle of numerical and physical studies is concerned with the task of a subsonic periodic flow around a semi-circular cylinder at Re = 5 × 10 4 [69,70]. It appeared that the ultra-low coefficients of the lift force C y of the order of −1 [85] (it was established by Z.P.…”