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

{"title":"ON THE EFFECTS OF VELOCITY PROFILES ON THE TOPOLOGICAL STRUCTURE OF A JET IN CROSS FLOW","authors":"D. New, T. Lim, S. Luo","doi":"10.1615/tsfp1.1040","DOIUrl":"https://doi.org/10.1615/tsfp1.1040","url":null,"abstract":"The effect of jet exit velocity profile on the topological structure of a round jet in a cross flow is investigated experimentally using the laser induced fluorescence technique. The study is focused on two velocity profiles, namely top-hat and parabolic profiles. The jet Reynolds number considered ranges from 350 to 1750, with the corresponding velocity ratios varying from 1 to 5. The results show that the top-hat jets are more unstable and likely to shed shear layer vortices than parabolic jets. Interestingly, it is found that the parabolic jets penetrate higher into the flow, but the largescale structures appear to be less coherent than those of the top-hat jets. These findings suggest that the characteristics of a jet in a cross flow is not only a function of the Reynolds number and the velocity ratio, but also a function of the shear layer thickness and hence velocity profile. INTRODUCTION The study of jets in cross flows (JICF) has immense relevance to engineering applications such as film cooling for turbine and combustors, fuel injection for burners, thrust reversers for propulsive systems as well as in the development of S/VTOL aircrafts. Its relevance in areas involving the dispersion of effluents in waterways and of pollutants in the atmosphere via chimneys and smoke stacks has long been recognized by the research community. Early research on JICF was confined mainly to determining the mean paths of the deflected jets (Jordinson, 1956 and Margason, 1968). Later, the focus was shifted to the measurement of the axial velocity decay and turbulence intensity along the jet axis by Keffer & Baines (1963), Pratte & Baines (1967) and Andreopoulos (1982 and 1985). Their results show that fluid entrainment and hence the mixing process, is substantially more intensive for a JICF than for a Figure 1 : Schematics of a jet in cross flow phenomenon as illustrated by Kelso et al (1996). free jet. This resulted in a surge of research focusing on better mixing of fluids. Recent studies see a rise in the use of computational simulations to predict both the fluid entrainment and the deflected jet trajectory as well as to verify earlier experimental work (Yuan & Street, 1996 and 1998). The numerical results of Yuan & Street looked promising and hold great potential for further investigations. A more detailed review of the subject over the last fifty years can be found in Margason (1993), Fric & Roshko (1994) and Kelso et al (1996). Earlier experimental work on JCIF has revealed a complex system of interacting vortical structures resulting from the interaction between a transverse round jet and a cross flow boundary layer (Figure 1). The main flow features can be summarised as follows: Flat wall Horseshoe vortex system Shear layer Counter-rotating vortex pair","PeriodicalId":222466,"journal":{"name":"Proceeding of First Symposium on Turbulence and Shear Flow Phenomena","volume":"46 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":"124429982","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 SIMULATION OF TURBULENT NON-EQUILIBRIUM METHANE-AIR JET FLAMES USING MONTE CARLO PDF METHOD","authors":"A. Hinz, E. Hassel, J. Janicka","doi":"10.1615/tsfp1.550","DOIUrl":"https://doi.org/10.1615/tsfp1.550","url":null,"abstract":"","PeriodicalId":222466,"journal":{"name":"Proceeding of First Symposium on Turbulence and Shear Flow Phenomena","volume":"5 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":"115666582","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":"DEFORMATION EFFECTS IN CASE OF A FLOW WITH STRETCHING OF POLYMER SOLUTIONS","authors":"V. Pogrebnyak, A. Pisarenko","doi":"10.1615/tsfp1.2160","DOIUrl":"https://doi.org/10.1615/tsfp1.2160","url":null,"abstract":"","PeriodicalId":222466,"journal":{"name":"Proceeding of First Symposium on Turbulence and Shear Flow Phenomena","volume":"83 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":"122636154","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":"RELATING PRESSURE FIELD AND VORTEX SHEDDING SUPPRESSION FOR A SQUARE CYLINDER IN THE VICINITY OF A SOLID WALL","authors":"O. Haidn, S. Bailey, R. Martinuzzi","doi":"10.1615/tsfp1.1660","DOIUrl":"https://doi.org/10.1615/tsfp1.1660","url":null,"abstract":"Surface pressure and wake velocity field fluctuations are investigated for a square cylinder mounted in the vicinity of a solid wall as functions of the boundary layer thickness and cylinder-to-wall gap heights for Reynolds numers between 20000 and 40000. The study focuses on the suppression of vortex shedding occurring around critical gap heights. Mean data are combined to identify three distinct flow regimes. Time and frequency analyses show that at large gap heights periodic vortex shedding is perturbed by underlying large-scale structures leading to phase jitter and long-term loss of correlation. For small gaps, there is no evidence of periodic motion. For intermediate gap heights, there is a gradual loss of correlation between the pressure field on the top and lower cylinder surfaces, which leads to periods of sinusoidal fluctuations interspersed with incoherent motion in the wake. It is found that the Reynolds number influence is negligible and that an increase in the boundary layer thickness results in a reduction of the critical gap height. Stability considerations suggest that a stable vortex street can only exist for a certain range of the top shear layer to bottom shear layer circulation ratio.","PeriodicalId":222466,"journal":{"name":"Proceeding of First Symposium on Turbulence and Shear Flow Phenomena","volume":"114 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":"124775883","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":"TURBULENT CHANNEL FLOW WITH STREAMWISE ROTATION: LIE GROUP ANALYSIS, DNS AND MODELING","authors":"M. Oberlack, W. Cabot, M. M. Rogers","doi":"10.1615/tsfp1.150","DOIUrl":"https://doi.org/10.1615/tsfp1.150","url":null,"abstract":"","PeriodicalId":222466,"journal":{"name":"Proceeding of First Symposium on Turbulence and Shear Flow Phenomena","volume":"31 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":"129656122","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":"MEASUREMENTS IN A FLAT PLATE TURBULENT BOUNDARY LAYER","authors":"J. M. Österlund, A. Johansson","doi":"10.1615/tsfp1.490","DOIUrl":"https://doi.org/10.1615/tsfp1.490","url":null,"abstract":"An experimental study has been made of flat plate turbulent boundary layers using hot-film and hot-wire techniques. The primary goals of the investigation were to investigate the scaling behavior of a turbulent boundary layer at high Reynolds numbers and especially the structure in the near wall region. Results are here presented for the mean velocity and Reynolds stresses for Reynolds numbers based on the momentum thickness ranging from 2500 to 27000. The high Re makes it necessary to use very small probes in order to resolve the smallest scales in the turbulence. A large effort has been put into the design and construction of miniaturized hot-wires for this experiment. Measurements of the fluctuating skin-friction were made with the hot-wire on the wall technique and a new surfacemicromachined MEMS-type hot-film sensor.","PeriodicalId":222466,"journal":{"name":"Proceeding of First Symposium on Turbulence and Shear Flow Phenomena","volume":"69 11 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":"129765516","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":"A GENERAL PARTICLE DISPERSION MODEL FOR LAGRANGIAN TRAJECTORY SIMULATION OF TWO-PHASE FLOWS IN CURVILINEAR COORDINATES","authors":"X. Chen, J. Pereira","doi":"10.1615/tsfp1.1370","DOIUrl":"https://doi.org/10.1615/tsfp1.1370","url":null,"abstract":"","PeriodicalId":222466,"journal":{"name":"Proceeding of First 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":"130086398","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":"OBSERVATIONS OF THE FORMATION OF STREAMWISE VORTICES","authors":"D. Heist, Y. Na, T. J. Hanratty","doi":"10.1615/tsfp1.50","DOIUrl":"https://doi.org/10.1615/tsfp1.50","url":null,"abstract":"","PeriodicalId":222466,"journal":{"name":"Proceeding of First Symposium on Turbulence and Shear Flow Phenomena","volume":"54 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":"127961299","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":"ON THE APPLICATION OF LARGE-EDDY SIMULATION TO PARTICLE-LADEN FLOWS","authors":"V. Armenio, U. Piomelli, V. Fiorotto","doi":"10.1615/tsfp1.240","DOIUrl":"https://doi.org/10.1615/tsfp1.240","url":null,"abstract":"","PeriodicalId":222466,"journal":{"name":"Proceeding of First 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":"129932644","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":"TURBULENT BOUNDARY LAYER SHEAR STRESS PULSES IN ADVERSE PRESSURE GRADIENT","authors":"V. A. Sandborn","doi":"10.1615/tsfp1.2090","DOIUrl":"https://doi.org/10.1615/tsfp1.2090","url":null,"abstract":"","PeriodicalId":222466,"journal":{"name":"Proceeding of First Symposium on Turbulence and Shear Flow Phenomena","volume":"237 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":"121792975","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}