Analysis of PDFs for energy transfer rates from 4096<sup>3</sup>DNS – verification of the scaling relation within MPDFT

Arimitsu, Toshihico; Arimitsu, Naoko

doi:10.1080/14685248.2010.524221

Cited by 16 publications

(6 citation statements)

References 30 publications

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“…Note that lim n→∞ ε n → ∞ for α < 1. The degree of singularity for energy dissipation rate is specified by the singularity exponent α which is considered to be a stochastic variable whose PDF, P (n) (α), is given by [10,11,12,13,14,17,18] the Rényi [20] or HCT [21,22] type PDF…”

Section: Aanda Modelmentioning

confidence: 99%

“…The variables q and α are related through q = [2/(1 − q) ln δ][(α − α 0 )/(α − α max )(α − α min )]. The qth moment of the energy dissipation rate is given by (ε n / ) q ∝ ( n / 0 ) −τ (q)+1−q [5,17,18]. With the assumption (9), we have, for…”

Section: Pdfs Of Energy Dissipation Rates With Aanda Modelmentioning

confidence: 99%

“…θ = 0.668 ln(r/η) + 0.585, (16) ln w = 0.280 ln(r/η) − 1.68, (17) ln ε * n = −0.727 ln(r/η) + 3.63, (18) which are obtained by the method of least squares using in each figure all the data points for δ = 2 1/4 , 2 1/2 and 2 altogether. The results given in Fig.…”

Section: Pdfs Of Energy Dissipation Rates With Aanda Modelmentioning

confidence: 99%

“…Only a few [8,12,13,14,15,16] analyze the probability density functions (PDFs) for physical quantities representing intermittent character. Among these researches, multifractal probability density function theory (MPDFT) [12,13,14,17,18] provides the most precise analysis of fat-tail PDFs, which is a statistical mechanical ensemble theory constructed by the authors (T.A. and N.A.)…”

Section: Introductionmentioning

confidence: 99%

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Towards a separation of the elements in turbulence via the analyses within MPDFT

Arimitsu,

Takechi

et al. 2011

Preprint

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The PDFs for energy dissipation rates created in a high resolution from 4096 3 DNS for fully developed turbulence are analyzed in a high precision with the PDF derived within the formula of multifractal probability density function theory (MPDFT). MPDFT is a statistical mechanical ensemble theory constructed in order to analyze intermittent phenomena through the experimental PDFs with fat-tail. By making use of the obtained w-PDFs created from the whole of the DNS region, analyzed for the first time are the two partial PDFs, i.e., the max-PDF and the min-PDF which are, respectively, taken out from the partial DNS regions of the size 512 3 with maximum and minimum enstropy. The main information for the partial PDFs are the following. One can find a w-PDF whose tail part can adjust the slope of the tail-part of a max-PDF with appropriate magnification factor. The value of the point at which the w-PDF multiplied by the magnification factor starts to overlap the tail part of the max-PDF coincides with the value of the connection point for the theoretical w-PDF. The center part of the min-PDFs can be adjusted quite accurately by the scaled w-PDFs with a common scale factor.

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Section: Aanda Modelmentioning

confidence: 99%

Section: Pdfs Of Energy Dissipation Rates With Aanda Modelmentioning

confidence: 99%

Section: Pdfs Of Energy Dissipation Rates With Aanda Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Towards a separation of the elements in turbulence via the analyses within MPDFT

Arimitsu,

Takechi

et al. 2011

Preprint

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“…DWT has evident advantages compared with CWT since it is invertible and multi-scaled scales can be analyzed. Kadoch [18] combined DWT and direct numerical simulation (DNS), whose results proved that coherent structures preserve the vortical structures with only about 4% of the wavelet coefficients but retain 99.9% of the turbulence energy.…”

Section: Introductionmentioning

confidence: 99%

Extracting Coherent Structures in Near-Wall Turbulence Based on Wavelet Analysis

Hai-Bao¹,

Huang²

2020

Advances in Complex Analysis and Applications

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To analyze the properties of the coherent structures in near-wall turbulence, an extraction method based on wavelet transform (WT) and a verification procedure based on correlation analysis are proposed in this work. The flow field of the turbulent boundary layer is measured using the hot-film anemometer in a gravitational low-speed water tunnel. The obtained velocity profile and turbulence intensity are validated with traditional boundary layer theory. The fluctuating velocities at three testing positions are analyzed. Using the power spectrum density (PSD) and WT, coherent and incoherent parts of the near-wall turbulence are extracted and analyzed. The probability density functions (PDFs) of the extracted signals indicate that the incoherent structures of turbulence obey the Gaussian distribution, while the coherent structures deviate from it. The PDFs of coherent structures and original turbulence signals are similar, which means that coherent structures make the most contributions to the turbulence entrainment. A correlation parameter is defined at last to prove the validity of our extraction procedure.

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Analysis of a Hybrid RANS/LES Model Using RANS Reconstruction

Nini

Abbà

Germano

et al. 2016

Springer Proceedings in Physics

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The Hybrid RANS/LES method proposed is based on the hybrid filter approach introduced by Germano in 2004. In this work, instead of using two explicit models respectively for LES and RANS, we use only a model for LES and we reconstruct the RANS field exploiting the properties of hybrid filter. The reconstruction is obtained from the resolved velocity and the LES subgrid stress tensor. The model has been implemented using a variational approach in a DG-FEM framework and tested for the turbulent channel flow test case. Different configurations for hybrid terms have been compared with DNS data and with pure LES results

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Analysis of PDFs for energy transfer rates from 4096³DNS – verification of the scaling relation within MPDFT

Cited by 16 publications

References 30 publications

Towards a separation of the elements in turbulence via the analyses within MPDFT

Towards a separation of the elements in turbulence via the analyses within MPDFT

Extracting Coherent Structures in Near-Wall Turbulence Based on Wavelet Analysis

Analysis of a Hybrid RANS/LES Model Using RANS Reconstruction

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Analysis of PDFs for energy transfer rates from 40963DNS – verification of the scaling relation within MPDFT

Cited by 16 publications

References 30 publications

Towards a separation of the elements in turbulence via the analyses within MPDFT

Towards a separation of the elements in turbulence via the analyses within MPDFT

Extracting Coherent Structures in Near-Wall Turbulence Based on Wavelet Analysis

Analysis of a Hybrid RANS/LES Model Using RANS Reconstruction

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Analysis of PDFs for energy transfer rates from 4096³DNS – verification of the scaling relation within MPDFT