{"title":"MEASUREMENT OF DEVELOPING TURBULENT FLOWS IN A ROTATING 90 DEGREE BEND WITH SQUARE CROSS-SECTION","authors":"Y. Choi, K. Chun, Dong Chul Kim","doi":"10.1615/tsfp2.2210","DOIUrl":"https://doi.org/10.1615/tsfp2.2210","url":null,"abstract":"","PeriodicalId":438618,"journal":{"name":"Proceeding of Second Symposium on Turbulence and Shear Flow Phenomena","volume":"111 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":"116574643","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":"STEREOSCOPIC PIV MEASUREMENTS IN A JET IN CROSSFLOW","authors":"K. Meyer, O. Ozcan, P. S. Larsen, C. Westergaard","doi":"10.1615/tsfp2.1870","DOIUrl":"https://doi.org/10.1615/tsfp2.1870","url":null,"abstract":"","PeriodicalId":438618,"journal":{"name":"Proceeding of Second 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":"121640344","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}
Pub Date : 1900-01-01DOI: 10.1088/1468-5248/3/1/028
E. Lamballais, J. Silvestrini
Direct numerical simulations of turbulent flows around a cylinder are performed using the virtual boundary technique to model the presence of the obstacle. This method consists of the imposition of a no-slip boundary condition within the flow field, using a specific forcing term added to the momentum equation. In this paper, two different inflow conditions are considered upstream from the cylinder. In the first case, where the inflow conditions correspond to a constant velocity flow, common features of the cylinder wake dynamics are well recovered (three-dimensional vortex shedding) while turbulent statistics (mean velocity and Reynolds stresses) are in good agreement with previous experimental and numerical results. This clearly shows that a code based on high-order finite difference schemes combined with the virtual boundary method can lead to reliable results even if the grid is not well designed for the shape of the obstacle. In the second case, the inflow conditions correspond to a spatially developi...
{"title":"DIRECT NUMERICAL SIMULATION OF INTERACTIONS BETWEEN A MIXING LAYER AND A WAKE AROUND A CYLINDER","authors":"E. Lamballais, J. Silvestrini","doi":"10.1088/1468-5248/3/1/028","DOIUrl":"https://doi.org/10.1088/1468-5248/3/1/028","url":null,"abstract":"Direct numerical simulations of turbulent flows around a cylinder are performed using the virtual boundary technique to model the presence of the obstacle. This method consists of the imposition of a no-slip boundary condition within the flow field, using a specific forcing term added to the momentum equation. In this paper, two different inflow conditions are considered upstream from the cylinder. In the first case, where the inflow conditions correspond to a constant velocity flow, common features of the cylinder wake dynamics are well recovered (three-dimensional vortex shedding) while turbulent statistics (mean velocity and Reynolds stresses) are in good agreement with previous experimental and numerical results. This clearly shows that a code based on high-order finite difference schemes combined with the virtual boundary method can lead to reliable results even if the grid is not well designed for the shape of the obstacle. In the second case, the inflow conditions correspond to a spatially developi...","PeriodicalId":438618,"journal":{"name":"Proceeding of Second Symposium on Turbulence and Shear Flow Phenomena","volume":"abs/2303.02094 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":"123794502","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":"DIRECT NUMERICAL SIMULATION OF AN IMPINGING JET","authors":"Yongmann M. Chung, K. Luo, John J. R. Williams","doi":"10.1615/tsfp2.1190","DOIUrl":"https://doi.org/10.1615/tsfp2.1190","url":null,"abstract":"","PeriodicalId":438618,"journal":{"name":"Proceeding of Second Symposium on Turbulence and Shear Flow Phenomena","volume":"22 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":"125252373","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 USING EXPLICIT FILTERING IN TURBULENT CHANNEL FLOW","authors":"J. Gullbrand","doi":"10.1615/tsfp2.1340","DOIUrl":"https://doi.org/10.1615/tsfp2.1340","url":null,"abstract":"","PeriodicalId":438618,"journal":{"name":"Proceeding of Second Symposium on Turbulence and Shear Flow Phenomena","volume":"20 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":"116514746","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}
The mixing efficiency in a turbulent mixing layer is quantified by monitoring the surface-area of level-sets of scalar fields. The Laplace transform is applied to numerically calculate integrals over arbitrary level-sets. The analysis includes both direct and large-eddy simulation and is used to assess the suitability of specific subgrid parameterizations in relation to predicting mixing efficiency. We incorporate several subgrid models in the comparison, e.g. the scale similarity model of Bardina, the dynamic eddy-viscosity model and the dynamic mixed model. For accurate predictions, dynamic models are favored. It is observed that the ratio between LES-filterwidth Δ and grid-spacing h has a considerable influence; a ratio of four appears suitable. Gravity driven flows can be modeled by 'active' scalar fields which couple to the momentum and energy equations. The significant increase in mixing efficiency due to buoyancy effects is directly quantified.
{"title":"LEVEL-SET DYNAMICS AND MIXING EFFICIENCY OF PASSIVE AND ACTIVE SCALARS IN DNS AND LES OF TURBULENT MIXING LAYERS","authors":"B. Geurts, Bert Vreman, H. Kuerten, K. Luo","doi":"10.1615/tsfp2.1050","DOIUrl":"https://doi.org/10.1615/tsfp2.1050","url":null,"abstract":"The mixing efficiency in a turbulent mixing layer is quantified by monitoring the surface-area of level-sets of scalar fields. The Laplace transform is applied to numerically calculate integrals over arbitrary level-sets. The analysis includes both direct and large-eddy simulation and is used to assess the suitability of specific subgrid parameterizations in relation to predicting mixing efficiency. We incorporate several subgrid models in the comparison, e.g. the scale similarity model of Bardina, the dynamic eddy-viscosity model and the dynamic mixed model. For accurate predictions, dynamic models are favored. It is observed that the ratio between LES-filterwidth Δ and grid-spacing h has a considerable influence; a ratio of four appears suitable. Gravity driven flows can be modeled by 'active' scalar fields which couple to the momentum and energy equations. The significant increase in mixing efficiency due to buoyancy effects is directly quantified.","PeriodicalId":438618,"journal":{"name":"Proceeding of Second Symposium on Turbulence and Shear Flow Phenomena","volume":"36 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":"134131307","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":"CONTROL OF DRAG REDUCTION OF FUNCTIONAL FLUID FLOW IN RECTANGULAR CHANNEL - SPATIAL STRUCTURE AND RECOVERY PROCESS OF TURBULENCE INVESTIGATED BY PIV -","authors":"Y. Kawaguchi, Z. Feng, Pei Li","doi":"10.1615/tsfp2.1400","DOIUrl":"https://doi.org/10.1615/tsfp2.1400","url":null,"abstract":"","PeriodicalId":438618,"journal":{"name":"Proceeding of Second Symposium on Turbulence and Shear Flow Phenomena","volume":"36 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":"124284581","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":"FULL WAY COUPLING OF LARGE EDDY SIMULATION FOR PARTICLE-LADEN TURBULENT FLOWS USING NEW DYNAMIC SGS MODELS","authors":"K. Lei, N. Taniguchi, Toshio Kobayashi","doi":"10.1615/tsfp2.920","DOIUrl":"https://doi.org/10.1615/tsfp2.920","url":null,"abstract":"","PeriodicalId":438618,"journal":{"name":"Proceeding of Second Symposium on Turbulence and Shear Flow Phenomena","volume":"22 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":"131552948","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}
T. Craft, A. Gerasimov, H. Iacovides, B. Launder, C. Robinson
{"title":"A NEW WALL FUNCTION STRATEGY FOR FORCED AND MIXED CONVECTION","authors":"T. Craft, A. Gerasimov, H. Iacovides, B. Launder, C. Robinson","doi":"10.1615/tsfp2.360","DOIUrl":"https://doi.org/10.1615/tsfp2.360","url":null,"abstract":"","PeriodicalId":438618,"journal":{"name":"Proceeding of Second Symposium on Turbulence and Shear Flow Phenomena","volume":"206 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":"134130444","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}
Markus Hogberg, T. Bewley, M. Berggren, D. Henningson
Using two diierent approaches to optimal control in channel ow an eeort is made to try to identify diierences and similarities. One approach is to use the Navier{Stokes equations and apply a gradient based optimization technique to nd the optimal control. The other approach is to make use of the linearized equations known as the Orr{Sommerfeld{Squire equations to compute the optimal control. Limiting ourselves to look only at oblique wave perturbations we compare the resulting energy evolution from application of the respective control strategies. Qualitatively the performance of the two approaches are similar, at least when they work under comparable conditions. The non-linear control can be more aggressive initially since there is no direct limitation on the time derivative of the control even though the discretization implicitly enforces some degree of penalty. Adjusting the parameters properly we can show that the control from the two approaches are very similar. Also we try to quantify the performance of the estimator based control, or compensation, using only measurements on the wall, compared to the full-state information control. The performance of the compensator is found to be good for small perturbations, especially if a good initial guess can be provided.
{"title":"OPTIMAL CONTROL OF TRANSITION INITIATED BY OBLIQUE WAVES IN CHANNEL FLOW","authors":"Markus Hogberg, T. Bewley, M. Berggren, D. Henningson","doi":"10.1615/tsfp2.260","DOIUrl":"https://doi.org/10.1615/tsfp2.260","url":null,"abstract":"Using two diierent approaches to optimal control in channel ow an eeort is made to try to identify diierences and similarities. One approach is to use the Navier{Stokes equations and apply a gradient based optimization technique to nd the optimal control. The other approach is to make use of the linearized equations known as the Orr{Sommerfeld{Squire equations to compute the optimal control. Limiting ourselves to look only at oblique wave perturbations we compare the resulting energy evolution from application of the respective control strategies. Qualitatively the performance of the two approaches are similar, at least when they work under comparable conditions. The non-linear control can be more aggressive initially since there is no direct limitation on the time derivative of the control even though the discretization implicitly enforces some degree of penalty. Adjusting the parameters properly we can show that the control from the two approaches are very similar. Also we try to quantify the performance of the estimator based control, or compensation, using only measurements on the wall, compared to the full-state information control. The performance of the compensator is found to be good for small perturbations, especially if a good initial guess can be provided.","PeriodicalId":438618,"journal":{"name":"Proceeding of Second Symposium on Turbulence and Shear Flow Phenomena","volume":"1123 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133842890","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}
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