An Overset Finite-Element Large-Eddy Simulation Method With Applications to Turbomachinery and Aeroacoustics

2003 ◽  
Vol 70 (1) ◽  
pp. 32-43 ◽  
Author(s):  
C. Kato ◽  
M. Kaiho ◽  
A. Manabe
Keyword(s):  
Finite Element ◽  
Fluid Flow ◽  
Flow Field ◽  
Moving Boundary ◽  
Far Field ◽  
Eddy Simulation ◽  
Unsteady Fluid Flow ◽  
Large Eddy ◽  
Unsteady Fluid ◽  
Field Sound

A numerical method for the prediction of an unsteady fluid flow in a complex geometry that involves moving boundary interfaces is presented in this paper. The method is also applicable to the prediction of the far-field sound that results from an unsteady fluid flow. The flow field is computed by large-eddy simulation (LES), while surface-pressure fluctuations obtained by the LES are used to predict the far-field sound. To deal with a moving boundary interface in the flow field, a form of the finite element method in which overset grids are applied from multiple dynamic frames of reference has been developed. The method is implemented as a parallel program by applying a domain-decomposition programming model. The validity of the proposed method is shown through two numerical examples: prediction of the internal flows of a hydraulic pump stage and prediction of the far-field sound that results from unsteady flow around an insulator mounted on a high-speed train.

Large Eddy Simulation of Slurry Erosion in Submerged Impinging Jets

2020 ◽  
Author(s):  
Qiuchen Wang ◽  
Qiyu Huang ◽  
Xu Sun ◽  
Jun Zhang ◽  
Soroor Karimi ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Flow Field ◽  
Large Eddy Simulation ◽  
Turbulence Models ◽  
Impinging Jets ◽  
Erosion Process ◽  
Slurry Erosion ◽  
Eddy Simulation ◽  
Erosion Prediction ◽  
Large Eddy

Abstract Submerged impingement jets are widely used in erosion/corrosion investigation as it is easy to control standoff distance as well as jet angle and flow velocities in experiments. In addition to experiments, typically Computational Fluid Dynamics (CFD) technique has been used to simulate slurry flow in this geometry to investigate erosion process and develop and verify erosion equations. This is done by solving Reynolds Averaged Navier-Stokes (RANS) equations with turbulence models, time-averaged fluid flow is revealed, and thus time-averaged erosion rate can be obtained by tracking particles in the fluid flow field. The current work shows that this seemingly simple flow displays unsteady flow structures in the stagnation zone of the flow field and its effects on erosion process was unclear. In this study, Large Eddy Simulation (LES) is used to simulate unsteady fluid flow in different impingement jets in Eulerian scheme. Then particles are injected randomly in the surface and tracked transiently to simulate unsteady erosion process in Lagrangian scheme. Finally, an erosion equation is used to calculate solid particle erosion rates. The LES Eulerian-Lagrangian erosion modeling are further validated by experimental fluid velocities and erosion profile measured before. It was found the accuracy of erosion prediction of small particles can be improved and unsteady properties can be well resolved by using this method.

Large Eddy Simulation of Unsteady Flow Around a Door Mirror Model and Prediction of Resulting Far-Field Sound

2005 ◽  
Author(s):  
Hong Wang ◽  
Chisachi Kato ◽  
Yoshinobu Yamade ◽  
Yang Guo
Keyword(s):  
Large Eddy Simulation ◽  
Unsteady Flow ◽  
Surface Pressure ◽  
Measured Data ◽  
Far Field ◽  
Acoustic Analogy ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Mesh Resolution ◽  
Field Sound

Unsteady flow and resulting far-field sound are numerically investigated for a door mirror model in this paper. The flow field is solved by Large Eddy Simulation (LES) with the dynamic Smagorinsky model while the surface pressure fluctuations obtained by LES are used to predict the far-field sound based on the acoustic analogy. For the prediction of the far-field sound, Curle’s equation is used under the assumption that the characteristic length of the door mirror model is much smaller than the wavelength of the sound. Comparisons between the predicted and measured data are presented in terms of the time-averaged and fluctuating surface pressure distributions as well as the far-field sound spectrum. Reasonably good agreements have been obtained between the predicted and the measured data. Investigation of the effects of the mesh resolution also shows that improved results can be obtained efficiently if the mesh resolution is increased along the stream-wise direction within the separation region and wake region.

Transient Large Eddy Simulation of Slurry Erosion in Submerged Impinging Jets

2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Qiuchen Wang ◽  
Qiyu Huang ◽  
Xu Sun ◽  
Jun Zhang ◽  
Soroor Karimi ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Flow Field ◽  
Large Eddy Simulation ◽  
Turbulence Models ◽  
Target Surface ◽  
Impinging Jets ◽  
Erosion Process ◽  
Slurry Erosion ◽  
Eddy Simulation ◽  
Large Eddy

Abstract Submerged impingement jets are widely used in erosion/corrosion experiments as it is easy to control jet standoff distance, jet angle, and flow velocities in experiments. In addition to experiments, typically computational fluid dynamics (CFD) technique has been used to simulate slurry flow in this geometry to investigate erosion process and develop erosion models or equations. The traditional CFD simulations of erosion in this geometry use the Reynolds-averaged Navier–Stokes (RANS) equations with turbulence models. By using this technique, time-averaged fluid flow is revealed, and thus, time-averaged erosion rate can be obtained by tracking particles in the fluid flow field. However, this seemingly simple flow displays unsteady flow structures in the stagnation zone of the flow field and its effects on the erosion process were previously unclear. In this study, large eddy simulation (LES) is used to simulate unsteady fluid flow in different impingement jets in an Eulerian scheme. Then, transient particle tracking is performed in a Lagrangian scheme. Particles are injected randomly at the inlet plane and tracked to simulate unsteady erosion that occurs on the target surface. Finally, an erosion equation is used to calculate solid particle erosion rates. The LES Eulerian–Lagrangian erosion modeling is further validated by available experimental data for fluid velocities and an erosion profile. The results show that the accuracy of erosion prediction of small particles is improved significantly by using the LES method. In addition, the unsteady particle motion and erosion process can be revealed by using this method.

scholarly journals A Comparative Study of Fluid Flow and Mass Transfer in a Trumpet-Shaped Ladle Shroud Using Large Eddy Simulation

2015 ◽  
Vol 47 (1) ◽  
pp. 495-507 ◽  
Author(s):  
Jiangshan Zhang ◽  
Jingshe Li ◽  
Yi Yan ◽  
Zhixin Chen ◽  
Shufeng Yang ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Fluid Flow ◽  
Large Eddy Simulation ◽  
Comparative Study ◽  
Eddy Simulation ◽  
Large Eddy

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

2005 ◽  
Vol 4 (1-2) ◽  
pp. 93-115 ◽  
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]).

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