Synthetic Inflow Boundary Conditions for Wall Bounded Flows

Jarrin, N; Uribe, Juan; Prosser, Robert; Laurence, Dominique

doi:10.1007/978-3-540-77815-8_8

Cited by 16 publications

(15 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Effects similar to those discussed here had been observed by P. Moin (private communication) and Jarrin (2007), associated in both cases with attempts to shorten the initial transient in large-eddy simulations of channels, but they were not analysed in detail. A distant precursor can also be found in the 'constrained Euler' simulations of isotropic turbulence with prescribed spectra, used to study the energy transfer and the behaviour of large-eddy simulations by Shtilman & Chasnov (1992), Jiménez (1993), She & Jackson (1993) and Zhou (1993), among others.…”

mentioning

confidence: 55%

Simulations of turbulent channels with prescribed velocity profiles

Tuerke

Jiménez

2013

J. Fluid Mech.

View full text Add to dashboard Cite

Direct numerical simulations of turbulent channels with artificially prescribed velocity profiles are discussed, using both natural and purposely incorrect profiles. It is found that turbulence develops correctly when natural profiles are prescribed, but that even slightly incorrect ones modify the Reynolds stresses substantially. That is used to study the dynamics of the energy-containing velocity fluctuations. The stronger (weaker) structures generated by locally stronger (weaker) mean shears have essentially correct isotropy coefficients but they are out of energy equilibrium, with the energy imbalance compensated by turbulent diffusion. The velocity scale in smooth profiles changes with the distance to the wall, and is best described by a friction velocity derived from the local total tangential stress. The behaviour across sharper shear jumps is more consistent with non-equilibrium eddies that relax over wall-normal distances of the order of the distance to the wall, suggesting that the energy equilibrium in the logarithmic layer is not local to a given height, but applies to extended layers homogenized by wall-normal fluxes. Examples of that non-local character are the large-scale inactive fluctuations near the wall, whose velocities do not scale with the local shear stress, but with that of their active 'cores' farther away from the wall.

show abstract

mentioning

confidence: 55%

Simulations of turbulent channels with prescribed velocity profiles

Tuerke

Jiménez

2013

J. Fluid Mech.

View full text Add to dashboard Cite

show abstract

“…Veloudis et al (2007) has also shown a variation of the method to work well in channel flow for LES. The synthetic eddy method has been shown to work well in channel flows (Jarrin et al, 2006(Jarrin et al, , 2008(Jarrin et al, , 2009. With a small adaption the synthetic eddy method can be constructed with the same advantages that the digital filter method has.…”

Section: Introductionmentioning

confidence: 99%

Large eddy simulation of a coaxial jet with a synthetic turbulent inlet

Abboud

Smith

2014

International Journal of Heat and Fluid Flow

View full text Add to dashboard Cite

This study analyzed the effects of two methods of synthetic inlet turbulence on the accuracy of coaxial, circular jet simulations with regards to experimental data. The two methods that were utilized in the study were a digital filter method and a synthetic eddy method. This study examines the implementation of these methods into an academic LES code, with extensive evaluation of the simulation data compared to experimental results. The results in the paper are presented for two different mesh resolutions, 22 and 8 million cells. The simulations were performed for three different velocity ratios of the annular to the inner jet: 0.0, 1.0 and 1.5. The inlet methods were utilized in two ways, one by setting the velocity fluctuation profile based on experimental data of the inlet flow, the second by setting an estimated isotropic-fluctuation profile. In this way, using the estimated method can be compared to using the prescribed fluctuations, which may not be usable if experimental data of the inlet is not available. When comparing the centerline profiles to the velocity data for the turbulent inlet, the data for velocity ratios 1.0 and 1.5 were improved compared to the experimental profiles. However, for the velocity ratio 0.0 case velocity data when using the turbulent inlet the data showed significant decay and did not match experimental profiles in the far field of the jet. The radial data for a velocity ratio of 0.0 showed better agreement with the experimental data in the jet spreading to develop the proper velocity profile. The velocity fluctuation data was the most accurate in the near field region when the turbulent inlet was used. A comparison can also be made between using a prescribed fluctuation inlet and just using the approximated

show abstract

“…A second solution is to filter white noise to reproduce imposed spatial and temporal correlations of the incoming turbulence, as proposed by Ewert et al 3 in the Random Particle Method (RPM) or by Dieste & Gabard. 4,5 Another alternative introduced by Jarrinet al, 6,7,8 the Synthetic Eddy Method (SEM), is based on the decomposition of the turbulence in a sum of eddies, calibrated to match the desired features of the turbulence.…”

Section: Introductionmentioning

confidence: 99%

CAA Study of Airfoil Broadband Interaction Noise Using Stochastic Turbulent Vorticity Sources<br />

Hainaut

Gabard

Clair

2015

21st AIAA/CEAS Aeroacoustics Conference

View full text Add to dashboard Cite

The interaction of the turbulent wakes of the rotor with the outer guide vanes is one of the main broadband noise source in turbofan engines at approach conditions. Hence its prediction and reduction is a priority for engine manufacturers. The development of numerical methods is required as analytical approaches are limited to simple geometries and simplified flow configurations. The linearized Euler equations are solved in the time-domain to model the response of an isolated airfoil interacting with turbulence that is stochastically synthesized and injected in the computational domain through vorticity sources. This new method of injection has the advantages of being easy to implement and parallelize in an existing solver, whilst the generated turbulence is frozen. The method is firstly validated on a 2D free-field configuration. It is then applied, in the framework of the Fan Stage Broadband Noise Benchmarking Programme, to a two-dimensional NACA 65(12)-10 airfoil with no angle of attack and the results are validated through comparisons with experimental data. Afterwards, the effect of the angle of attack is studied and the results suggest that a one-component turbulent model is not satisfactory to perform accurate acoustic predictions with an angle of attack, as it overestimates the rate of decay of the acoustic spectra at high frequencies. The study of the influence of the integral length scale of the turbulence confirms that the airfoil leading edge response is only modulated by the incoming turbulence characteristics. Finally, the acoustic spectra predicted for different velocities show a better agreement with a flat plate analytical model when the velocity is increased.

show abstract

Synthetic Inflow Boundary Conditions for Wall Bounded Flows

Cited by 16 publications

References 8 publications

Simulations of turbulent channels with prescribed velocity profiles

Simulations of turbulent channels with prescribed velocity profiles

Large eddy simulation of a coaxial jet with a synthetic turbulent inlet

CAA Study of Airfoil Broadband Interaction Noise Using Stochastic Turbulent Vorticity Sources<br />

Contact Info

Product

Resources

About