Development of a Large Eddy and Detached Eddy Simulation Capability for Broadband Noise Prediction on Unstructured Meshes (Invited)

The Wall-modeled Large-eddy Simulation (WMLES) methods are commonly accompanied with an underprediction of the skin friction and a deviation of the velocity profile. The widely-used Improved Delayed Detached Eddy Simulation (IDDES) method is suggested to improve the prediction of the mean skin friction when it acts as WMLES, as claimed by the original authors. However, the model tested only on flow configurations with no heat transfer. This study takes a systematic approach to assess the performance of the IDDES model for separated flows with heat transfer. Separated flows on an isothermal wall and walls with mild and intense heat fluxes are considered. For the case of the wall with heat flux, the skin friction and Stanton number are underpredicted by the IDDES model however, the underprediction is less significant for the isothermal wall case. The simulations of the cases with intense wall heat transfer reveal an interesting dependence on the heat flux level supplied; as the heat flux increases, the IDDES model declines to predict the accurate skin friction.

Download Full-text

Wake-Airfoil Interaction as Broadband Noise Source: A Large-Eddy Simulation Study

International Journal of Aeroacoustics ◽

10.1260/1475472053730093 ◽

2005 ◽

Vol 4 (1-2) ◽

pp. 93-115 ◽

Cited By ~ 37

Author(s):

Jérôme Boudet ◽

Nathalie Grosjean ◽

Marc C. Jacob

Keyword(s):

Large Eddy Simulation ◽

Particle Image ◽

Broadband Noise ◽

Far Field ◽

Acoustic Analogy ◽

Eddy Simulation ◽

Naca0012 Airfoil ◽

Image Velocimetry ◽

Large Eddy ◽

Proper Orthogonal

A large-eddy simulation is carried out on a rod-airfoil configuration and compared to an accompanying experiment as well as to a RANS computation. A NACA0012 airfoil (chord c = 0.1 m) is located one chord downstream of a circular rod (diameter d = c/10, Red = 48 000). The computed interaction of the resulting sub-critical vortex street with the airfoil is assessed using averaged quantities, aerodynamic spectra and proper orthogonal decomposition (POD) of the instantaneous flow fields. Snapshots of the flow field are compared to particle image velocimetry (PIV) data. The acoustic far field is predicted using the Ffowcs Williams & Hawkings acoustic analogy, and compared to the experimental far field spectra. The large-eddy simulation is shown to accurately represent the deterministic pattern of the vortex shedding that is described by POD modes 1 & 2 and the resulting tonal noise also compares favourably to measurements. Furthermore higher order POD modes that are found in the PIV data are well predicted by the computation. The broadband content of the aerodynamic and the acoustic fields is consequently well predicted over a large range of frequencies ([0 kHz; 10 kHz]).

Download Full-text

A parallel implicit domain decomposition algorithm for the large eddy simulation of incompressible turbulent flows on 3D unstructured meshes

International Journal for Numerical Methods in Fluids ◽

10.1002/fld.4695 ◽

2018 ◽

Vol 89 (9) ◽

pp. 343-361 ◽

Cited By ~ 2

Author(s):

Zi-Ju Liao ◽

Rongliang Chen ◽

Zhengzheng Yan ◽

Xiao-Chuan Cai

Keyword(s):

Large Eddy Simulation ◽

Domain Decomposition ◽

Turbulent Flows ◽

Unstructured Meshes ◽

Decomposition Algorithm ◽

Eddy Simulation ◽

Large Eddy ◽

Domain Decomposition Algorithm

Download Full-text

An Explicit Filtering Method for Large Eddy Simulation on Unstructured Meshes

40th Fluid Dynamics Conference and Exhibit ◽

10.2514/6.2010-5025 ◽

2010 ◽

Author(s):

Fabien Griman ◽

Marc Terracol ◽

Pierre Sagaut

Keyword(s):

Large Eddy Simulation ◽

Unstructured Meshes ◽

Filtering Method ◽

Eddy Simulation ◽

Large Eddy

Download Full-text

Detailed Investigation of Detached-Eddy Simulation for the Flow Past a Circular Cylinder at Re=3900

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.232.471 ◽

2012 ◽

Vol 232 ◽

pp. 471-476 ◽

Cited By ~ 3

Author(s):

Rui Zhao ◽

Chao Yan

Keyword(s):

Reynolds Number ◽

Circular Cylinder ◽

Flow Structures ◽

Detached Eddy Simulation ◽

Eddy Simulation ◽

Flow Past ◽

Large Eddy ◽

Mesh Resolution ◽

Physical Phenomena

The flow past a circular cylinder at a subcritical Reynolds number 3900 was simulated by the method of detached-eddy simulation (DES). The objective of this present work is not to investigate the physical phenomena of the flow but to study modeling as well as numerical aspects which influence the quality of DES solutions in detail. Firstly, four typical spanwise lengths are chosen and the results are systematically compared. The trend of DES results along the span increment is different from previous large-eddy simulation (LES) investigation. A wider spanwise length does not necessary improve the results. Then, the influence of mesh resolution is studied and found that both too coarse and over refined grids will deteriorate the performance of DES. Finally, different orders of numerical schemes are applied in the inviscid fluxes and the viscous terms. The discrepancies among different schemes are found tiny. However, the instantaneous flow structures produced by 5th order WENO with 4th order central differencing scheme are more abundant than the others. That is, for the time-averaged quantities, the second-order accurate schemes are effective enough, whereas the higher-order accurate methods are needed to resolve the transient characteristics of the flow.

Download Full-text