Turbulent momentum and passive scalar transport in supersonic channel flow

Friedrich, Rainer; Foysi, Holger; Sesterhenn, Jörn

doi:10.1590/s1678-58782006000200007

Cited by 4 publications

(10 citation statements)

References 13 publications

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“…Evolution of bulk Mach number MB w (3.1a), ratio of centerline-to-wall static temperatures, and wall-to-theoretical-adiabatic-wall temperatures (3.1e), as a function of centerline Mach numberMCL (3.1d), for various Reynolds numbers, using the present large-box DNS results (Tab. 2) and other available DNS data Friedrich et al 2006;Wei & Pollard 2011a,b). channel case (Coleman et al 1995, Tab.…”

Section: Compressible Channel Flowmentioning

confidence: 96%

“…1) covering, although without a systematic variation of both parameters, the range Re τ ∈ [64,344] Friedrich et al 2006;Tamano & Morinishi 2006;Gerolymos et al 2010;Wei & Pollard 2011b) cover the range Re τ ∈ [150, 300] and M CL ∈ [0.35, 2.25], again without systematic variation of both parameters. The spatial resolution of the present large-box (L x ×L y ×L z = 8πδ ×2δ ×4πδ) computations (Tab.…”

Section: Dns Computationsmentioning

confidence: 99%

“…1), with repect to usual compressible channel DNS standards Friedrich et al 2006;Tamano & Morinishi 2006;Gerolymos et al 2010;Wei & Pollard 2011b). Nonetheless, the transport equations for the variances and fluxes of thermodynamic variables contain complicated terms ( §4.1- §4.4), including triple correlations of gradients of the fluctuating field and correlations containing the fluctuating dilatation Θ , which require higher resolution to achieve grid convergence, compared to the basic 2-order moments (Gerolymos et al 2010).…”

Section: Budgetsmentioning

confidence: 99%

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Pressure, density, temperature and entropy fluctuations in compressible turbulent plane channel flow

Gerolymos

Vallet

2014

J. Fluid Mech.

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We investigate the fluctuations of thermodynamic state-variables in compressible aerodynamic wall-turbulence, using results of direct numerical simulation (DNS) of compressible turbulent plane channel flow. The basic transport equations governing the behaviour of thermodynamic variables (density, pressure, temperature and entropy) are reviewed and used to derive the exact transport equations for the variances and fluxes (transport by the fluctuating velocity field) of the thermodynamic fluctuations. The scaling with Reynolds and Mach number of compressible turbulent plane channel flow is discussed. Correlation coefficients and higher-order statistics of the thermodynamic fluctuations are examined. Finally, detailed budgets of the transport equations for the variances and fluxes of the thermodynamic variables from a well-resolved DNS are analysed. Implications of these results both to the understanding of the thermodynamic interactions in compressible wall-turbulence and to possible improvements in statistical modelling are assessed. Finally, the required extension of existing DNS data to fully characterise this canonical flow is discussed.

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Section: Compressible Channel Flowmentioning

confidence: 96%

Section: Dns Computationsmentioning

confidence: 99%

Section: Budgetsmentioning

confidence: 99%

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Pressure, density, temperature and entropy fluctuations in compressible turbulent plane channel flow

Gerolymos

Vallet

2014

J. Fluid Mech.

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“…44 This results in significant turbulence anisotropy within the near wake region and explains the very different turbulence amplifications of the turbulence intensities. Direct numerical simulations ͑DNS͒ performed by Friedrich et al 45 have demonstrated that the absolute pressure-strain correlation terms are typically smaller in compressible flows than in corresponding incompressible flows. One might therefore intuitively expect that the energy transfer process due to the pressure-strain correlation terms will diminish with increasing compressibility, thereby suppressing the redistribution of streamwise turbulence energy to the other components.…”

Section: -9mentioning

confidence: 99%

Unsteady flow organization of compressible planar base flows

2007

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The unsteady flow features of a series of two-dimensional, planar base flows are examined, within a range of low-supersonic Mach numbers in order to gain a better understanding of the effects of compressibility on the organized global dynamics. Particle image velocimetry is used as the primary diagnostic tool in order to characterize the instantaneous near wake behavior, in combination with data processing using proper orthogonal decomposition. The results show that the mean flowfields are simplified representations of the instantaneous flow organizations. Generally, each test case can be characterized by a predominant global mode, which undergoes an evolution with compressibility, within the Mach number range considered. ͑The term "global mode" is defined herein as an organized global dynamical behavior of the near wake region, recognizing that the near wake dynamics may be describable in terms of several global modes.͒ At Mach 1.46, the predominant global mode can be characterized by a sinuous or flapping motion. With increasing compressibility, this flapping mode decreases, and the predominant global mode evolves into a pulsating motion aligned with the wake axis at Mach 2.27. These global modes play an important role in the distributed nature of the turbulence properties. The turbulent mixing processes become increasingly confined to a narrower redeveloping wake with increasing compressibility. Global maximum levels of the streamwise turbulence intensity and the kinematic Reynolds shear stress occur within the vicinity of the mean reattachment location, and show no systematic trend with compressibility. In contrast, the global maximum level of the vertical turbulence intensity moves upstream from the redeveloping wake toward the mean reattachment location. The vertical turbulence intensity decays thereafter more slowly than the other turbulence quantities. Overall, the local maximum levels of the turbulence properties decrease appreciably with increasing compressibility.

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“…Throughout the study, we use the superscript to represent the normalization with , the friction velocity , the friction temperature (denoted as , , is the mean heat flux on the wall), the viscous length scale (denoted as , , ) and the friction scalar , which is defined as (Friedrich et al. 2006) We also use the superscript to represent the normalization with the semilocal wall units, i.e. and .…”

Section: Numerical Simulation Set-upsmentioning

confidence: 99%

On the streamwise velocity, temperature and passive scalar fields in compressible turbulent channel flows: a viewpoint from multiphysics couplings

Cheng,

2024

J. Fluid Mech.

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It is generally believed that the velocity and passive scalar fields share many similarities and differences in wall-bounded turbulence. In the present study, we conduct a series of direct numerical simulations of compressible channel flows with passive scalars and employ the two-dimensional spectral linear stochastic estimation and the correlation function as diagnostic tools to shed light on these aspects. Particular attention is paid to the relevant multiphysics couplings in the spectral domain, i.e. the velocity–temperature ( $u-T$ ), scalar–temperature ( $g-T$ ) and velocity–scalar ( $u-g$ ) couplings. These couplings are found to be utterly different at a given wall-normal position in the logarithmic and outer regions. Specifically, in the logarithmic region, the $u-T$ and $u-g$ couplings are tight at the scales that correspond to the attached eddies and the very large-scale motions (VLSMs), whereas the $g-T$ coupling is robust in the whole spectral domain. In the outer region, $u-T$ and $u-g$ couplings are only active at the scales corresponding to the VLSMs, whereas the $g-T$ coupling is diminished but still strong at all scales. Further analysis indicates that although the temperature field in the vast majority of zones in a channel can be roughly treated as a passive scalar, its physical properties gradually deviate from those of a pure passive scalar as the wall-normal height increases due to the enhancement of the acoustic mode. Furthermore, the deep involvement of the pressure field in the self-sustaining process of energy-containing motions also drives the streamwise velocity fluctuation away from a passive scalar. The current work is an extension of our previous study (Cheng & Fu, J. Fluid Mech., vol. 964, 2023, A15), and further uncovers the details of the multiphysics couplings in compressible wall turbulence.

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Turbulent momentum and passive scalar transport in supersonic channel flow

Cited by 4 publications

References 13 publications

Pressure, density, temperature and entropy fluctuations in compressible turbulent plane channel flow

Pressure, density, temperature and entropy fluctuations in compressible turbulent plane channel flow

Unsteady flow organization of compressible planar base flows

On the streamwise velocity, temperature and passive scalar fields in compressible turbulent channel flows: a viewpoint from multiphysics couplings

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