Implementation of Delayed Detached Eddy Simulation method to a high order spectral difference solver

2017 ◽  
Vol 154 ◽  
pp. 90-101 ◽  
Author(s):  
Junhui Gao ◽  
Xiaodong Li
Keyword(s):  
Simulation Method ◽  
High Order ◽  
Detached Eddy Simulation ◽  
Spectral Difference ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation

A DDES study of the flow past a prolate spheroid using a high-order U-MUSCL scheme

2020 ◽  
Vol 34 (14n16) ◽  
pp. 2040075
Author(s):  
Yu-Chen Yang ◽  
Zhen-Ming Wang ◽  
Ning Zhao
Keyword(s):  
Flow Separation ◽  
Vortex Structure ◽  
Prolate Spheroid ◽  
High Order ◽  
Detached Eddy Simulation ◽  
Complex Flow ◽  
Eddy Simulation ◽  
Flow Past ◽  
Delayed Detached Eddy Simulation ◽  
Flow Phenomena

Flow past a prolate spheroid, which is a representative simplified configuration for vehicles such as maneuvering ships, submarines and missiles, comprises a series of complex flow phenomena including pressure-induced flow separation, which results in unsteady forces and movements that may be detrimental to vehicles’ performance. In this paper, a Delayed Detached Eddy Simulation (DDES) method combined with a new high-order U-MUSCL scheme is proposed to more precisely and accurately capture the flow separation and vortex structure. This method is applied to simulate the aerodynamic performance of the 6:1 prolate spheroid at an AOA of [Formula: see text] with the Reynolds number of [Formula: see text]. Axial pressure distribution of five individual chord wise sections and flow field structure of the aft body are analyzed. Numerical results agree well with the experimental data. It can be concluded that DDES combined with three-order U-MUSCL scheme demonstrates reliable performance since it captures the vortex structure of aft body distinctly and predicts the separation and reattachment points of the secondary vortex precisely.

scholarly journals Delayed detached Eddy simulation of wing flutter boundary using high order schemes

2017 ◽  
Vol 71 ◽  
pp. 199-216 ◽  
Author(s):  
Jia-ye Gan ◽  
Hong-Sik Im ◽  
Xiang-ying Chen ◽  
Ge-Cheng Zha ◽  
Crystal L. Pasiliao
Keyword(s):  
High Order ◽  
Detached Eddy Simulation ◽  
High Order Schemes ◽  
Wing Flutter ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation ◽  
Flutter Boundary

Delayed Detached-Eddy Simulation and Application of a Coflow Jet Airfoil at High Angle of Attack

2013 ◽  
Vol 444-445 ◽  
pp. 270-276
Author(s):  
Wen Biao Gan ◽  
Zhou Zhou ◽  
Xiao Ping Xu ◽  
Rui Wang
Keyword(s):  
Angle Of Attack ◽  
Aircraft Design ◽  
Simulation Method ◽  
Detached Eddy Simulation ◽  
High Angle ◽  
High Angle Of Attack ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation ◽  
Flow Vortex ◽  
Cylinder Flow

A DDES (Delayed Detached-Eddy Simulation) method is presented and applied to simulation and design of a CFJ (Coflow Jet) airfoil at high angle of attack. The method is based on average vorticity, and is used to predict a number of test cases, including a circular cylinder flow, vortex design and simulation of the CFJ airfoil. The results demonstrate that the DDES method is efficient for CFJ airfoil flow. It provides reference to flow control and aircraft design.

scholarly journals High-order detached-eddy simulation method based on a Reynolds-stress background model

2017 ◽  
Vol 66 (18) ◽  
pp. 184701
Author(s):  
Wang Sheng-Ye ◽  
Wang Guang-Xue ◽  
Dong Yi-Dao ◽  
Deng Xiao-Gang
Keyword(s):  
Reynolds Stress ◽  
Simulation Method ◽  
High Order ◽  
Background Model ◽  
Detached Eddy Simulation ◽  
Eddy Simulation

Numerical simulation of the effects of obstacle deflectors on the aerodynamic performance of stationary high-speed trains at two yaw angles

2017 ◽  
Vol 232 (3) ◽  
pp. 913-927 ◽  
Author(s):  
Ji-qiang Niu ◽  
Dan Zhou ◽  
Xi-feng Liang
Keyword(s):  
High Speed ◽  
Simulation Method ◽  
Aerodynamic Performance ◽  
Wake Flow ◽  
Detached Eddy Simulation ◽  
Aerodynamic Forces ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation ◽  
High Speed Trains ◽  
Yaw Angle

In this study, based on the shear-stress transport κ–ω turbulent model, the improved delayed detached eddy simulation method has been used to simulate the unsteady aerodynamic performance of trains with different obstacle deflectors at two yaw angles (0° and 15°). The numerical algorithm is used and some of the numerical results are verified through wind tunnel tests. By comparing and analysing the obtained results, the effects of the obstacle deflectors on the force of the trains as well as the pressure and flow structure around the trains are elucidated. The results show that the obstacle deflectors primarily affect the flow field at the bottom of the head car as well as the wake flow, and that the internal oblique-type obstacle deflector (IOOD) markedly improves the aerodynamic performance of the trains, by decreasing most of the aerodynamic forces of the train cars and minimising their fluctuations. Further, a nonzero yaw angle weakens or even changes the effect of the IOOD on the aerodynamic forces of the train cars. However, the effect of the IOOD is more on the tail car.

scholarly journals Enhanced Delayed Detached Eddy Simulation for Cavities and Labyrinth Seals

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Richard J. Jefferson-Loveday
Keyword(s):  
Labyrinth Seal ◽  
High Order ◽  
Experimental Measurements ◽  
Detached Eddy Simulation ◽  
Specific Flow ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation ◽  
New Variant ◽  
Wide Range ◽  
Original Definition

Abstract A range of popular hybrid Reynolds-averaged Navier–Stokes -large eddy simulation (RANS-LES) methods are tested for a cavity and two labyrinth seal geometries using an in-house high-order computational fluid dynamics (CFD) code and a commercial CFD code. The models include the standard Spalart–Allmaras (SA) and Menter shear stress transport (SST) versions of delayed detached eddy simulation (DDES) and the Menter scale adaptive simulation (SAS) model. A recently formulated, enhanced, variant of SA-DDES presented in the literature and a new variant using the Menter SST model are also investigated. The latter modify the original definition of the subgrid length scale used in standard DDES based on local vorticity and strain. For all geometries, the meshes are considered to be hybrid RANS-LES adequate. Very low levels of resolved turbulence and quasi-two-dimensional flow fields are observed for the standard DDES and SAS models even for the test cases here that contain obstacles, sharp edges, and swirling flow. Similar findings are observed for both the commercial and in-house high-order CFD codes. For the cavity simulations, when using standard DDES and SAS, there is a significant under prediction of turbulent statistics compared with experimental measurements. The enhanced versions of DDES, on the other hand, show a significant improvement and resolve turbulent content over a wide range of scales. Improved agreement with experimental measurements is also observed for profiles of the vertical velocity component. For the first labyrinth seal geometry swirl velocities are more accurately captured by the enhanced DDES versions. For the second labyrinth seal geometry, the mass flow coefficient prediction using the enhanced models is significantly improved (up to 30%). Standard, industrially available hybrid RANS-LES models, when applied to the present canonical cases can produce little to no resolved turbulent content. The standard SA- and Menter-based DDES models can yield lower levels of eddy viscosity when compared to equivilent steady RANS simulations which means that they are not operating as RANS or LES. It is recommended that hybrid RANS-LES models should be extensively tested for specific flow configurations and that special care is exercised by CFD practitioners when using many of the popular hybrid RANS-LES models that are currently available in commercial CFD packages.

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