Volume 1: Flow Manipulation and Active Control; Bio-Inspired Fluid Mechanics; Boundary Layer and High-Speed Flows; Fluids Engineering Education; Transport Phenomena in Energy Conversion and Mixing; Turbulent Flows; Vortex Dynamics; DNS/LES and Hybrid RANS/LES Methods; Fluid Structure Interaction; Fl最新文献

{"title":"Investigation on Loading-Induced Fluid Flow in Osteogenesis Imperfecta Bone","authors":"N. V. Shrivas, A. Tiwari, Rakesh Kumar, D. Tripathi, Vasu Raman Sharma","doi":"10.1115/FEDSM2018-83496","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83496","url":null,"abstract":"Osteogenesis Imperfecta (OI) is a genetic bone disorder which is typically characterized by brittle bones with frequent fractures. It is also known as brittle bone disease. Surgical procedure is one of the ways adopted by clinicians for the management of OI. In recent years, it has however become clear that physical activity is equally important for managing OI in both children and adults. Exogenous mechanical stimulation e.g. prophylactic exercises may be useful in improving the bone mass and strength of OI bones as loading-induced mechanical components e.g. normal strain and canalicular fluid flow stimulate remodeling activities. Several studies have characterized the strain environment in OI bones, whereas, very few studies attempted to characterize the canalicular fluid flow. In the present study, we anticipate that canalicular fluid flow reduces in OI bone as compared to healthy bone under physiological loading. This work accordingly computes the canalicular fluid distribution in the single osteon model of OI and control/normal bones subjected to normal physiological loadings. A transversely isotropic poroelastic model of osteon is developed. Loading is applied in accordance with gait cycles reported for OI and healthy bones. Fluid distribution patterns computed for OI and healthy bones are compared at different time-points of stance phase of the gait cycle. A significant reduction in fluid flow is observed in case of OI bone as compared to healthy bone. This clearly indicates that improvements in physical activities or exercises can be designed to enhance the level of canalicular fluid flow to initiate possible osteogenic activities and the bone.","PeriodicalId":23480,"journal":{"name":"Volume 1: Flow Manipulation and Active Control; Bio-Inspired Fluid Mechanics; Boundary Layer and High-Speed Flows; Fluids Engineering Education; Transport Phenomena in Energy Conversion and Mixing; Turbulent Flows; Vortex Dynamics; DNS/LES and Hybrid RANS/LES Methods; Fluid Structure Interaction; Fl","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86038415","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":"Effect of Fluid Properties on Slug Dissipation in Enlarged Impacting Tee","authors":"Mobina Mohammadikharkeshi, Ramin Dabirian, O. Shoham, R. Mohan","doi":"10.1115/FEDSM2018-83313","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83313","url":null,"abstract":"An experimental and theoretical investigation is conducted on the effect of inlet slug length and fluid properties on slug dissipation in an enlarged impacting tee-junction (EIT). The EIT is the building block of a multiphase manifold. Prediction of the slug dissipation length in the EIT provides a guideline for the optimum diameter and length of a manifold. A multiphase flow loop is utilized to investigate slug dissipation in an EIT. The EIT inlet pipe is inclined slightly upward at 5 degrees, in which stationary slugs of different lengths are formed. The generated slugs are pushed into the EIT branches by a pre-determined gas flow rate. Over 80 experimental runs are conducted with superficial gas velocities between 3 to 9 m/s and inlet slug lengths between 40d to 90d, for both air-water and air-oil flows. The experimental data confirm that increasing the superficial gas velocity, as well as the slug body length in the inlet pipe lead to increasing the slug dissipation length in the EIT branches. Furthermore, the data demonstrate that higher slug dissipation length is obtained with water as compared to oil. A mechanistic model is developed for the prediction of slug dissipation in an EIT. A comparison between the developed mechanistic model predictions and the experimental data show a discrepancy less than 20%.","PeriodicalId":23480,"journal":{"name":"Volume 1: Flow Manipulation and Active Control; Bio-Inspired Fluid Mechanics; Boundary Layer and High-Speed Flows; Fluids Engineering Education; Transport Phenomena in Energy Conversion and Mixing; Turbulent Flows; Vortex Dynamics; DNS/LES and Hybrid RANS/LES Methods; Fluid Structure Interaction; Fl","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86440790","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":"Analysis of Pressure Field on Wire-Wrapped Pin Bundle Surface for Concerns of FSI","authors":"L. Brockmeyer, A. Obabko, E. Merzari, Y. Hassan","doi":"10.1115/FEDSM2018-83521","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83521","url":null,"abstract":"Wire wrapped fuel pins, typical of sodium fast reactor designs, introduce a strong secondary rotational flow and enhanced mixing compared to bare pins found in many other nuclear reactor designs. The transverse flow is created by deflection off of the helical wires, exerting a force onto the wires. The resulting pressure field can be more intricate than found for bare fuel pins. There is an increased concern for fluid structure interactions such as twisting, bending, and vibration due to the fluid deflection and increased transverse flow. The present study uses LES to simulate the fluid flow in a wire-wrapped fuel pin bundle. The simulation is performed using Nek5000, a spectral element LES/DNS code. The time-dependent, fluctuating pressure field at the surface of select fuel pins are specifically captured for analysis. Statistical analysis is performed on the pressure data to find areas of persistent force or bending moment, which over large periods of time may result in deformation of the pins. Further, the pressure data is analyzed in search of areas with large fluctuations in pressure, which may result in flow induced vibrations. Frequency spectra of the force fluctuations are analyzed.","PeriodicalId":23480,"journal":{"name":"Volume 1: Flow Manipulation and Active Control; Bio-Inspired Fluid Mechanics; Boundary Layer and High-Speed Flows; Fluids Engineering Education; Transport Phenomena in Energy Conversion and Mixing; Turbulent Flows; Vortex Dynamics; DNS/LES and Hybrid RANS/LES Methods; Fluid Structure Interaction; Fl","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79700547","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":"Evaluation of Models for Droplet Shear Effect of Centrifugal Pump","authors":"Ramin Dabirian, S. Cui, I. Gavrielatos, R. Mohan, O. Shoham","doi":"10.1115/FEDSM2018-83318","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83318","url":null,"abstract":"During the process of petroleum production and transportation, equipment such as pumps and chokes will cause shear effects which break the dispersed droplets into smaller size. The smaller droplets will influence the separator process significantly and the droplet size distribution has become a critical criterion for separator design. In order to have a better understanding of the separation efficiency, estimation of the dispersed-phase droplet size distribution is very important. The objective of this paper is to qualitatively and quantitatively investigate the effect of shear imparted on oil-water flow by centrifugal pump.\u0000 This paper presents available published models for the calculation of droplet size distribution caused by different production equipment. Also detailed experimental data for droplet size distribution downstream of a centrifugal pump are presented. Rosin-Rammler and Log-Normal Distributions utilizing dmax Pereyra (2011) model as well as dmin Kouba (2003) model are used in order to evaluate the best fit distribution function to simulate the cumulative droplet size distribution. The results confirm that applying dmax Pereyra (2011) model leads to Rosin-Rammler distribution is much closer to the experimental data for low shear conditions, while the Log-Normal distribution shows better performance for higher shear rates. Furthermore, the predictions of Modified Kouba (2003) dmin model show good results for predicting the droplet distribution in centrifugal pump, and even better predictions under various ranges of experiments are achieved with manipulating cumulative percentage at minimum droplet diameter F(Dmin).","PeriodicalId":23480,"journal":{"name":"Volume 1: Flow Manipulation and Active Control; Bio-Inspired Fluid Mechanics; Boundary Layer and High-Speed Flows; Fluids Engineering Education; Transport Phenomena in Energy Conversion and Mixing; Turbulent Flows; Vortex Dynamics; DNS/LES and Hybrid RANS/LES Methods; Fluid Structure Interaction; Fl","volume":"177 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76931359","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":"Influence of Numerical Dissipation on Draft Tube Flows","authors":"Yao Jiang, Liu Yang, S. Nadarajah","doi":"10.1115/FEDSM2018-83225","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83225","url":null,"abstract":"Hydro-turbines are operated at loads above or below the best efficiency point (over- or part-load), where turbulent flow structures are formed in the draft tube. The goal of the project is to investigate turbulent flows present in the draft tube through a thorough numerical investigation. In the context of numerical simulations, a focus is made on the numerical scheme. Steady and unsteady simulations with the k-ωom SST turbulence model are applied with a novel eddy-preserving limiter scheme for draft tube flows. The application of the eddy-preserving limiter scheme allows to better resolve the flow field. Numerical results are validated through a comparison to experimental data.","PeriodicalId":23480,"journal":{"name":"Volume 1: Flow Manipulation and Active Control; Bio-Inspired Fluid Mechanics; Boundary Layer and High-Speed Flows; Fluids Engineering Education; Transport Phenomena in Energy Conversion and Mixing; Turbulent Flows; Vortex Dynamics; DNS/LES and Hybrid RANS/LES Methods; Fluid Structure Interaction; Fl","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82902837","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":"Multi-Plane Characterization of the Turbulent Boundary Layer","authors":"K. Dennis, K. Siddiqui","doi":"10.1115/FEDSM2018-83507","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83507","url":null,"abstract":"The boundary layers are known for their significance in several engineering systems. In particular, the inner region of the turbulent boundary layer has been shown to play a significant role in controlling the dynamics of turbulent structures that are responsible for the transport of mass, heat and momentum. While substantial work has been done in the past to characterize the structure of turbulent flow in this region, the characterization of the three-dimensional turbulent flow structure is limited. This study reports a multi-plane particle image velocimetry (PIV) approach to investigate three-dimensional dynamics of the turbulent boundary layer in the near-wall region. Planar PIV is used to capture two-dimensional fluid velocity fields in several planes with respect to the fluid flow direction. These results are used to describe three-dimensional turbulent events given by key quantities such as mean and turbulent velocities and turbulent kinetic energy.","PeriodicalId":23480,"journal":{"name":"Volume 1: Flow Manipulation and Active Control; Bio-Inspired Fluid Mechanics; Boundary Layer and High-Speed Flows; Fluids Engineering Education; Transport Phenomena in Energy Conversion and Mixing; Turbulent Flows; Vortex Dynamics; DNS/LES and Hybrid RANS/LES Methods; Fluid Structure Interaction; Fl","volume":"1990 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88191586","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":"Assessment of RANS, LES, and Hybrid RANS/LES Models for the Prediction of Low-Pr Turbulent Flows","authors":"S. Bhushan, O. Elfajri, W. Jock, D. K. Walters, J. Lai, Y. Hassan, R. Jackson, A. Obabko, E. Merzari","doi":"10.1115/FEDSM2018-83307","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83307","url":null,"abstract":"The predictive capability of RANS, hybrid RANS/LES and LES turbulence models for momentum and thermal energy transfer in wall bounded low-Pr turbulent flows is investigated. Plane channel flow simulations are performed for Reτ = 150 and 640 for Pr = 0.025 and 0.71 with and without buoyancy effects, including both forced and mixed force/natural convection conditions, using the open source spectral element flow solver Nek5000. The prediction of one-point velocity and temperature statistics from the simulations are compared against available DNS results. Results are analyzed to understand the effect of flow conditions on turbulent thermal transport, and assess the relative strengths and weaknesses of the different modeling methods.","PeriodicalId":23480,"journal":{"name":"Volume 1: Flow Manipulation and Active Control; Bio-Inspired Fluid Mechanics; Boundary Layer and High-Speed Flows; Fluids Engineering Education; Transport Phenomena in Energy Conversion and Mixing; Turbulent Flows; Vortex Dynamics; DNS/LES and Hybrid RANS/LES Methods; Fluid Structure Interaction; Fl","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84687767","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":"An Experimental Study of Surface-Mounted Bluff Bodies Immersed in Deep Turbulent Boundary Layers","authors":"Helen Amorin, Xingjun Fang, M. Tachie","doi":"10.1115/FEDSM2018-83498","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83498","url":null,"abstract":"This paper reports an experimental study conducted to investigate the effects of aspect ratio on the reattachment length and statistical properties in turbulent flow over three-dimensional surface-mounted bluff bodies. This study focuses on a surface-mounted body whose height is significantly smaller than the thickness of the approaching turbulent boundary layer. The studied aspect ratios of the step range from w/h = 0.5 to 20, where w and h denote the spanwise width and height of the step, respectively. All experiments were carried out in an open water channel, and the velocity measurements were performed using a time-resolved particle image velocimetry (TR-PIV) system. The Reynolds number, based on the freestream of the approach boundary layer and step height, is 12540, while the ratio of the boundary layer to step height is 4.83. Two distinct regions of separation are observed on top of the step and downstream of the step. In both separation regions, the reattachment length increases monotonically as aspect ratio increases from w/h = 0.5 to 8, and the reattachment length reaches an asymptotic value and does not vary significantly with aspect ratio larger than 8. The effects of aspect ratios on the mean velocities and Reynolds stresses were also examined.","PeriodicalId":23480,"journal":{"name":"Volume 1: Flow Manipulation and Active Control; Bio-Inspired Fluid Mechanics; Boundary Layer and High-Speed Flows; Fluids Engineering Education; Transport Phenomena in Energy Conversion and Mixing; Turbulent Flows; Vortex Dynamics; DNS/LES and Hybrid RANS/LES Methods; Fluid Structure Interaction; Fl","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84634840","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":"Experimental Observation of Bubbles Released in Horizontal Water Flow","authors":"C. Kang, Yanguang Ji, Lili Zhang, Wei Zhang","doi":"10.1115/FEDSM2018-83185","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83185","url":null,"abstract":"To investigate the characteristics of the bubble which is exposed to the liquid cross flow, the method of ventilation was adopted and air was injected into the water flow. A water tunnel was used to provide uniform water flow with variable velocity magnitude. A high speed camera was used to record instantaneous bubble images. An image-processing code was developed to identify bubble profile and to calculate bubble parameters. The effects of water flow velocity and the flow rate of the injected air were considered. The results indicate that bubble size decreases as the water velocity increases; meanwhile, ellipsoidal bubble shape is transformed into rounded shape. The variation in the air flow rate leads to a slight change of bubble size as well the bubble shape. The bubble velocity fluctuates with the movement of the bubble, and the fluctuations are intensified as the water velocity decreases. As the balance between the forces exerted on the bubble is reached, an approximately linear relationship between the bubble velocity and the water flow velocity is proven. For a given bubble equivalent diameter, the bubble terminal velocity with the liquid cross flow is higher than that associated with stagnant water. For small Eötvös number, the consistency of the bubble aspect ratio in the cross flow and the stagnant water is manifested; however, large Eötvös number obtained here is beyond the range associated with the stagnant water, and the existing relationship is extended.","PeriodicalId":23480,"journal":{"name":"Volume 1: Flow Manipulation and Active Control; Bio-Inspired Fluid Mechanics; Boundary Layer and High-Speed Flows; Fluids Engineering Education; Transport Phenomena in Energy Conversion and Mixing; Turbulent Flows; Vortex Dynamics; DNS/LES and Hybrid RANS/LES Methods; Fluid Structure Interaction; Fl","volume":"76 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90337530","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":"Effect of Liquid Level on Gas Carry-Under in GLCC Compact Separators","authors":"S. Kolla, R. Mohan, O. Shoham","doi":"10.1115/FEDSM2018-83301","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83301","url":null,"abstract":"Gas Carry-Under (GCU) is one of the two undesirable phenomena that occurs in the GLCC©1 (Gas-Liquid Cylindrical Cyclone) separators. Initial studies have shown that maintaining liquid level below the inlet of the GLCC© under control configuration affects the GCU in GLCC©. Also, it has been hypothesized that effective formation of vortex that is formed in the lower part of the GLCC©, or a stable gas core enhances the separation of gas entrained in the liquid. However, there has not been a systematic study on the effect of liquid level and the stability of the vortex on the GCU. This detailed and extensive experimental study attempts to fill that gap, investigating the effect of different liquid levels maintained below the inlet on the GCU. These studies are performed under the NOC (Normal operating Conditions) below the OPEN for liquid carry-over using control configuration to maintain the liquid level in the GLCC©. This study focuses on measuring the cumulative GCU in the liquid leg of the GLCC© over a period of time. The experimental investigations for GCU are conducted in a state of the art experimental facility for air-water and air-oil flow incorporating pressure and level control configurations. The experiments were carried out using a 3″ diameter GLCC© equipped with gas trap sections to measure simultaneously the GCU in the liquid leg of the GLCC©. The equilibrium liquid level is controlled at 4 different settings starting at 6″ below the GLCC© inlet and increasing to 2 feet below the inlet. It has been observed that the liquid level has tremendous effect on the complex swirling flow behavior in the lower part of the GLCC© and vortex stability, which in turn affects the GCU in the liquid leg of the GLCC©. Also, it has been noted that the liquid level has a significant effect on the Gas Void-Fraction in the liquid leg of the GLCC©, which is a critical parameter for multiphase pump operations.","PeriodicalId":23480,"journal":{"name":"Volume 1: Flow Manipulation and Active Control; Bio-Inspired Fluid Mechanics; Boundary Layer and High-Speed Flows; Fluids Engineering Education; Transport Phenomena in Energy Conversion and Mixing; Turbulent Flows; Vortex Dynamics; DNS/LES and Hybrid RANS/LES Methods; Fluid Structure Interaction; Fl","volume":"101 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76828773","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}