Proceeding of Tenth International Symposium on Turbulence and Shear Flow Phenomena最新文献

{"title":"COMPARING THE THREE POSSIBLE SCALINGS OF STREAM-WISE NORMAL STRESS IN TURBULENT BOUNDARY LAYERS","authors":"P. Monkewitz, H. Nagib, Vincent Boulanger","doi":"10.1615/tsfp10.1080","DOIUrl":"https://doi.org/10.1615/tsfp10.1080","url":null,"abstract":"","PeriodicalId":266791,"journal":{"name":"Proceeding of Tenth International Symposium on Turbulence and Shear Flow Phenomena","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121542309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The dependence of uniform momentum zones on mean shear and turbulence intensity","authors":"R. J. Hearst, B. Ganapathisubramani","doi":"10.1615/tsfp10.650","DOIUrl":"https://doi.org/10.1615/tsfp10.650","url":null,"abstract":"","PeriodicalId":266791,"journal":{"name":"Proceeding of Tenth International Symposium on Turbulence and Shear Flow Phenomena","volume":"885 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122277091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RESPONSES OF TURBULENT CHANNEL FLOWS TO TEMPORAL ACCELERATION","authors":"Seo Yoon Jung, Kyoungyoun Kim","doi":"10.1615/tsfp10.110","DOIUrl":"https://doi.org/10.1615/tsfp10.110","url":null,"abstract":"The effects of mean flow acceleration on near-wall turbulent structures were investigated by performing direct numerical simulations of transient turbulent flows in a channel. The simulations were initiated with a fully developed turbulent channel flow and then temporal accelerations were applied. During the acceleration, almost linearly increasing excursions of the flow rate were imposed between the steady initial and final values. The initial Reynolds number (based on the friction velocity) was fixed to Reτ,i = 180, and four different final Reynolds numbers (Reτ, f = 250, 300, 350, and 395) were selected to show the effects of the Reynolds number ratio (Reτ, f /Reτ,i) on the transient channel flows. To elucidate the effects of the flow acceleration rates on the near-wall turbulence, a wide range of acceleration durations has been examined. Various turbulent statistics and instantaneous flow fields revealed that the rapid increase in the flow rate invokes bypass-transition-like phenomena in the transient flow. In contrast, the flow evolves progressively and the transition does not occur clearly for the mild flow acceleration. When the increase in the Reynolds number is small during the acceleration, distinct bypass-like transition phenomena do not appear in the transient flows, regardless of the acceleration rate. The present study proposed new criteria based on the impulse of the acceleration in order to explain the transition to the new turbulence in the transient channel flow. The bypass-like transition is primarily due to the larger contribution of the impulse to the increase in the flow rate compared with that in viscous friction.","PeriodicalId":266791,"journal":{"name":"Proceeding of Tenth International Symposium on Turbulence and Shear Flow Phenomena","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129157295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large-eddy simulation of the high-Reynolds-number flow through a high-aspect-ratio cooling duct","authors":"Thomas Kaller, V. Pasquariello, S. Hickel, N. Adams","doi":"10.1615/tsfp10.1180","DOIUrl":"https://doi.org/10.1615/tsfp10.1180","url":null,"abstract":"We present well-resolved large-eddy-simulations (LES) of a straight, high-aspect-ratio cooling duct (HARCD) at a bulk Reynolds number of Re = 110 • 103 and an average Nusselt number of Nu = 371. The geometry and boundary conditions have been defined together with Rochlitz et al. (2015), who conducted the experimental measurements for this case. Water was chosen as coolant. The current investigation focuses on the influence of asymmetrical wall heating on the flow field and specifically on the influence of the turbulence-induced secondary flow on turbulent heat transfer, the spatial development of the temperature boundary layer and the accompanying viscosity modulation. Due to the viscosity drop in the vicinity of the heated wall we observe a decrease in turbulent length scales and in turbulence anisotropy, resulting in a decrease of turbulent mixing and the secondary flow strength along the duct.","PeriodicalId":266791,"journal":{"name":"Proceeding of Tenth International Symposium on Turbulence and Shear Flow Phenomena","volume":"36 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125729466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"REYNOLDS DECOMPOSITION OF TURBULENCE CONTAINING SUPER-COHERENT STATES","authors":"R. Adrian, P. Sakievich, Y. Peet","doi":"10.1615/tsfp10.270","DOIUrl":"https://doi.org/10.1615/tsfp10.270","url":null,"abstract":"We address the problem that occurs when time average values of mean and higher-order statistics of certain flows fail to exhibit the symmetry properties imposed by boundary conditions and physics. Such failures render determinations of the mean fields suspect, making it difficult, or even incorrect to apply Reynolds decomposition. We have been studying turbulent Rayleigh-Benard convection (RBC) in a 6.3:1 (diameter:depth) aspect-ratio vertical cylinder (Sakievich, et al. 2016), and it will be used as example to illustrate and explain this phenomenon. However, there are reasons to believe that the concepts that are developed from RBC pertain to other turbulent flows. In unit aspect ratio cylinders, it is commonly observed that the mean flow is non-zero (Bodenschatz, et al.; Emran, et al. 2015). We find from HPC simulations that turbulent RBC in a wide circular cylinder characteristically contains large-scale motions that are mean-square-periodic in the azimuthal-direction. In plan view they look like a somewhat randomly centered hub of rising (falling) fluid from which ‘spokes’ emanate in radial directions, iFgure 1. The spokes are convergence zones of warm (cool) fluid rising (falling) between horizontal, radially oriented, counter-rotating roll-cells. The most energetic roll cells have azimuthal periodicity Figure 1. RBC flow pattern at 109 Rayleigh number in a cylindrical geometry The flow is averaged over 600 free-fall times.","PeriodicalId":266791,"journal":{"name":"Proceeding of Tenth International Symposium on Turbulence and Shear Flow Phenomena","volume":"189 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133887010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The mesolayer of attached eddies in wall-bounded turbulent flows","authors":"Y. Hwang","doi":"10.1615/tsfp10.60","DOIUrl":"https://doi.org/10.1615/tsfp10.60","url":null,"abstract":"It has recently been reported that the outer peak in the secondorder statistics of the streamwise velocity depends on the Reynolds number. Starting from this puzzling observation, here I propose that the streamwise velocity component of each of the energy-containing motions in the form of Towsnend’s attached eddies exhibit innerscaling nature in the region close to the wall (see figure 1). Some compelling evidence on this proposition has been presented with a careful inspection of scaling of velocity spectra from direct numerical simulations and a linear analysis with an eddy viscosity. It is shown that this behavior can emerge due to inhomogeneous turbulent dissipation in the wall-normal direction, and also enables one to explain the Reynolds-number-dependent behavior of the outer peak as well as the near-wall penetration of the large-scale outer structures in a consistent manner. Extension of this concept to Townsend’s attached eddy hypothesis further reveals that the selfsimilarity in the streamwise velocity of the attached eddies would be theoretically broken in the region close to the wall.","PeriodicalId":266791,"journal":{"name":"Proceeding of Tenth International Symposium on Turbulence and Shear Flow Phenomena","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132142476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The response of the wall shear stress in uniformly and nonuniformly accelerating pipe flows","authors":"J. Sundström, M. Cervantes","doi":"10.1615/tsfp10.470","DOIUrl":"https://doi.org/10.1615/tsfp10.470","url":null,"abstract":"Wall shear stress measurements in an accelerating turbulent pipe flow have been performed. Four different imposed accelerations have been studied including one uniform and three nonuniform ones. Th ...","PeriodicalId":266791,"journal":{"name":"Proceeding of Tenth International Symposium on Turbulence and Shear Flow Phenomena","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124665039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SENSITIVITY OF A NEW VELOCITY/PRESSURE-GRADIENT MODEL TO THE REYNOLDS NUMBER","authors":"S. Poroseva, S. Murman","doi":"10.1615/tsfp10.1090","DOIUrl":"https://doi.org/10.1615/tsfp10.1090","url":null,"abstract":"The paper presents results of validation of a new model for velocity/pressure-gradient correlations in planar wall-bounded incompressible turbulent flows. The model belongs to a class of data-driven models and was obtained from the analysis of direct numerical simulation (DNS) data collected in a fully developed channel flow at Reτ = 392. It includes only the terms originally present in the transport equations for the Reynolds stresses. In the paper, sensitivity of the model coefficients to the flow Reynolds number and geometry is tested using three other DNS databases, with the Reynolds numbers, Reτ and Reθ , varying from 392 to 5200 in a fully developed channel flow and from 300 to 6500 in a zeropressure-gradient boundary-layer over a flat plate, respectively. In addition, the model is validated using DNS data in a strained channel flow at eight strain times including those that cause the flow to separate. It is demonstrated that no tuning of the model coefficients is required to accurately reproduce the behaviour of velocity/pressure-gradient correlations right to the wall in all considered flows. INTRODUCTION When simulating turbulent flows with the Reynolds-averaged Navier-Stokes (RANS) equations, models for unknown terms in the equations are required. Among such terms are velocity/pressure-gradient (VPG) correlations. Traditional approach to modelling the VPG correlations can be traced back to Chou (1945) and is based on the analysis of the exact integro-differential expressions for the VPG correlations. In the approach, the goal is to preserve tensor properties of the twopoint turbulence statistics that are integrated over the entire flow domain in models for one-point VPG correlations. Various linear and non-linear models were developed in such a manner over the years (see, e.g., Hanjalić and Launder, 2011). However, as demonstarted by many studies, values of model coefficients have to vary in any of these models. Ad-hoc or empirical corrections have to be implemented into a model to describe the turbulent flow features in different flow geometries and at different Reynolds numbers, also near a wall, under rotation etc. A presence of the flow separation reduces predictive capability of such models as well. In Poroseva and Murman (2014a), we analysed the major assumptions used in the traditional approach to modelling onepoint VPG correlations, proposed new models for the VPG correlations up to the fourth order, which are free of the homogeneous flow assumption, and analysed predictive capabilities of the derived models in a priori testing with DNS data in planar wall-bounded flows (Spalart, 1988; Sillero et al., 2013; Jeyapaul et al., 2015). The study led us to conclude that the traditional approach is unlikely to result in models for VPG correlations that are accurate near a wall. A more promising approach to modelling VPG correlations in wall-bounded flows was proposed in Poroseva and Murman (2014a,b). In the approach, model expressions ","PeriodicalId":266791,"journal":{"name":"Proceeding of Tenth International Symposium on Turbulence and Shear Flow Phenomena","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121816898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical and Experimental Investigation of the Flow around a three-dimensional SD7003 Wing","authors":"E. Tangermann, M. Klein, S. Herbst, R. Hain, C. Kähler","doi":"10.1615/tsfp10.740","DOIUrl":"https://doi.org/10.1615/tsfp10.740","url":null,"abstract":"","PeriodicalId":266791,"journal":{"name":"Proceeding of Tenth International Symposium on Turbulence and Shear Flow Phenomena","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127161672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesizing Wall Turbulence","authors":"B. McKeon","doi":"10.1615/tsfp10.10","DOIUrl":"https://doi.org/10.1615/tsfp10.10","url":null,"abstract":"","PeriodicalId":266791,"journal":{"name":"Proceeding of Tenth International Symposium on Turbulence and Shear Flow Phenomena","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120944832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}