Day 1 :
Keynote Forum
Hassan Hemida
University of Birmingham, UK
Keynote: Recent developments in train aerodynamics
Time : 10:25-11:05
Biography:
Hassan Hemida is a senior Lecturer and the Head of Research at the School of Civil Engineering, University of Birmingham. He is also the Director of the MRes in Railway System and Integration. He has a PhD in the field of crosswind flow around ground vehicles and his research interests range from fundamental thermo-fluids and CFD (LES, and, DES) to applied computational wind engineering. He has more than fifteen years of working experience in both academia and industry running research projects that involve steady and unsteady simulations of single and multiphase flows, with special emphases on wind engineering and train aerodynamics.
Abstract:
Traditionally, train aerodynamics was limited to the study of train drag reduction. Recently with the introduction of high-speed trains, the field of train aerodynamics became more and more important and of a direct concern to both train operators and manufacturers and new areas of research have been emerging. These include safety of trains in strong crosswinds, slipstream, noise and vibration, pressure pulses in tunnels and many other issues. Due to its own complexity and expenses, the measurements of aerodynamic phenomena on a full-scale train at the operating speed is extremely difficult and thus most of the researches of the aerodynamics of high-speed trains rely on small-scale physical modelling and computational fluid dynamics (CFD) techniques. Each of these has its own issues, however. The use of Computational Fluid Dynamics (CFD) to study train aerodynamics is an ever changing field due to continual increase in computational power. As new approaches become more viable, research must be conducted upon their validity. In this talk, the recent development of the use of CFD in train aerodynamics will be presented, starting from the drag reduction, crosswind forces on trains, slipstream and train pressure pulses on tunnels. Part of this talk will be also looking at the different CFD techniques and their validity for train aerodynamics and how they compare with model and full scale experiments.
Keynote Forum
Josep M Bergada
Polytechnic University of Catalonia, Spain
Keynote: Active flow control from fluidic oscillators to future applications
Time : 10:25-11:05
Biography:
Josep M Bergadà studied Mechanical Engineering at ETSEIAT (Escola Tècnica Superior d'Enginyeries Industrial i Aeronàutica de Terrassa)-UPC in 1990. He also did his PhD in Mechanical Engineering, Fluid Power Systems, at the same institution in 1996. During the period 2000 to 2010, he closely worked in the fluid power field with Prof. J Watton at Cardiff University, UK. His research focused on low Reynolds fluid mechanics applied to piston pumps and conical seat relief valves. During the period 2010-2014, his research was mostly based on collaboration with TU-Berlin, and focused on active flow control, studding the different fluidic oscillators and their possible applications. At present, active flow control applications as well as fluidic oscillator performance are his main research interests. He has over 50 international conference publications and journal papers, as well as several books on Fluid Mechanics and Fluid Power. He is currently an Editorial Board Member of an SCI journal.
Abstract:
It is well known that modifying the boundary layer separation point involves the modification of the forces acting onto a given bluff body. Traditionally, the separation point was usually delayed using passive flow control devices. Cars, trucks and aeroplanes have many of these devices. Quite recently, it was realized that the use of active flow control devices was producing very similar effects, having the capability of being switched on and off at users will and therefore implementing a new degree of freedom in the system where they are inserted. Regarding active flow control (AFC) devices, there are many possible configurations. AFC can be implemented using steady blowing or sucking, yet many researchers have observed that periodic forcing interacts more deeply with the boundary layer, therefore producing a huge modification to it and to the flow main parameters. When considering periodic forcing, it is relevant to evaluate the different fluidic oscillators, among them, the synthetic jets and fluidic actuators are the ones being more extensively used. During the presentation, some novel characteristics on fluidic actuators will be presented. Once the forcing device is chosen, the next step is to determine the location or locations the grooves need to be inserted. Groove location depends on the forcing system employed, forcing frequency as well as the momentum coefficient associated to the jet. At this point of the speech, some examples will be provided clarifying the effect onto the boundary layer and the downstream vortex shedding of several (AFC) devices. For some given applications, the optimum parameters regarding groove location, width, velocity ratio, etc., will be stablished. The speech will finish giving a list of possible future applications of (AFC).
- Fluid Dynamics | Numerical Methods | CFD Methodology & Models
Chair
Olga V. Mitrofanova
National Nuclear Research University MEPhI, Russia
Co-Chair
Yeng-Yung Tsui
National Chiao Tung University, Taiwan
Session Introduction
Alex Neves Junior
Federal University of Mato Grosso, Brazil
Title: A study of the fluidic movement of the hydrated products from the early carbonation curing in cementitious paste and the effects on the mechanical and porosity properties
Biography:
Alex Neves Junior has completed his PhD from Federal University of Rio de Janeiro. At moment, he is Adjunct Professor at the Federal University of Mato Grosso and Member of the Brazilian Association of Thermal Analysis. He was invited to participate in the book "Who is Who in Thermal Analysis and Calorimetry" by the Springer Publishing Company. He is Reviewer of the Journal of Thermal Analysis and Calorimetry and Building Construction and Materials. Two patents are requested by him: “Non-Conventional Thermogravimetry System in Controlled Chamber” and “New System of Non-Conventional Differential Thermal Analysis in Controlled Chamber”.
Abstract:
In a previous work, the authors achieved the best environmental conditions to capture CO2 in a high initial strength and sulfate-resistant Portland cement pastes after 24 hours of carbonation. However the samples that were totally carbonated with the consumption of all Ca(OH)2 had their mechanical properties affected. The samples presented a high initial water to cement ratio in the moment of treatment and considering that they were treated with carbon dioxide at early stages with a high initial porosity in a low relative humidity ambient, the flow of the fluids to the inner parts to outer parts of the samples, affected the distribution and the amount of the hydrated and carbonated products formed. The aim of this work was to analyze by thermogravimetry (TG), derivative thermogravimetry (DTG) and compressive strength test, considering different times of carbonation, the distribution of the hydrated and carbonated products formed in the profile of the samples and the relationship with the mechanical properties.
Iurii Sharikov
National Mineral Resources University, Russia
Title: Development of mathematical models of technological processes with using heat flux calorimetry
Biography:
Iurii Sharikov has completed his PhD from Leningrad Technological Institute, Leningrad, USSR and received his Grade of Doctor of Science in Mendeleev Chemical and Technological Institute Moscow, USSR. In 1976, he received the title of Professor in specialty of Chemical Engineering. He is Professor of the Mining University, St. Petersburg. He is focusing on researches in field of mathematical modeling and optimal control. He is author of more than 150 papers in reputed journals and serves as an Editorial Board Member of repute.
Abstract:
Mathematical modeling of processes in the chemical and metallurgical industries is widely used nowadays to create industrial production on the basis of experimental studies of the processes in the laboratory. A common method for creating mathematical models of processes is the synthesis of heat and mass transfer equations on the basis of dynamics equations of moving phases and source terms that express the kinetics of chemical reactions and phase transitions and thermal effects. To investigate the kinetics of chemical reactions in multistage polyphase systems, it is very effective to use the heat flux calorimetry in conjunction with the analysis of the composition in characteristic points in the heat generation curves. Using this technique, we have conducted studies of the kinetics of chemical reactions in the process of producing cement clinker and in the preparation of alumina in tubular rotating kilns, as well as processes for the modification of epoxy resins to enhance their functionality. On the basis of experimental data, the parameters of kinetic models were determined by solving the inverse kinetic problems and verified the adequacy of the obtained models. Created on the basis of these kinetics data, mathematical models of reactor unit have been used for the optimization of processes in industrial conditions. Optimization tasks have been solved using the method of nonlinear programming in the environment of a specialized software package for the development and analysis of mathematical models of reactor units. Special structure of control system has been developed for the implementation of discussed processes.
Asher Yahalom
Ariel University, Israel
Title: A finite element approach derived from the simplified variational principle
Biography:
Asher Yahalom is a Professor in the Faculty of Engineering at Ariel University and the Academic Director of the Free Electron Laser User Center which is located within the university center campus. He received BSc, MSc and PhD degrees in Mathematics and Physics from the Hebrew University in Jerusalem, Israel in 1990, 1991 and 1996 respectively. He was a Postdoctoral Fellow in 1998 at the Department of Electrical Engineering of Tel-Aviv University, Israel. He was a Visiting Fellow at the University of Cambridge, UK during the years 2005-2006, 2008 and 2012.
Abstract:
In previous papers, we have described how by minimizing the fluid action numerically one can obtain a solution of the fluid steady state equations. The action which was used was the four function action of Seliger & Whitham. In a recent paper, Yahalom & Lynden-Bell described how one can improve upon previous art by reducing the number of variables in the action. Three independent functions variational formalism for stationary and non-stationary barotropic flows were introduced. This is less than the four variables which appear in the standard equations of fluid dynamics which are the velocity field 
and the density ρ. Here we suggest a finite element approach to solve the reduced equations.
Zhengfang Qian
Naval Academy of Armament, China
Title: Research on sheet cavitation numerical predicted and estimation of tip vortex cavitation inception of ducted propeller with pre-swirl stator
Biography:
Zhengfang Qian has completed his Master’s degree in 2000. He is a Professor at Naval Academy of Armament. His major is Marine Propeller. He has published more than 20 papers in reputed journals and has been serving as an Editorial Board Member of repute.
Abstract:
In the paper, the research on sheet cavitation numerical predicted and estimation of tip vortex cavitation inception of ducted propeller with pre-swirl stator behind underwater vehicle was carried out. Firstly, the sheet cavitation shape of ducted propeller with pre-swirl stator was numerically simulated using a hybrid mesh based on RANS (Reynolds Averaged Navier Stokes) solver. A Singhal cavitation model based on transport equation was coupled in the RANS solver. The predicted sheet cavitation shapes were in good agreement with experimental observation. The overall results suggest that the present approach on predicting sheet cavitation shape of propeller behind underwater vehicle is practicable. Secondly, the wetted flow of ducted propeller with pre-swirl stator behind underwater vehicle was simulated, and the tip vortex cavitation inception was estimated based on the minimum pressure value on the propeller tip section. The results were also in good agreement with experimental results. It showed that the approach on estimation of tip vortex cavitation inception is feasible.
Josep M Bergada
Polytechnic University of Catalonia, Spain
Title: Active flow control applied on a NACA 2412 profile, possible devices to use and its expected performance efficiency
Biography:
Josep M Bergada completed his PhD in Mechanical Engineering in 1996 at Universitat Politecnica de Catalunya UPC-Spain, from the year 2000 to 2010 collaborated with Cardiff University UK, in evaluating the performance of piston pumps and valves, both used in the fluid power sector. From the year 2010 to 2014, he developed part of his research activities at TU-Berlin where he studied active flow control devices like fluidic actuators and synthetic jets. At the present, his research is related to Active Flow Control and his academic activities are based on lecturing Fluid Mechanics I and II at UPC. He has 26 years’ experience of lecturing at UPC. He published 12 papers at SCI journals, over 45 papers in conferences and two main books on Fluid Mechanics and Fluid Power. He is member of the editorial board of an SCI Journal
Abstract:
Flow control, whether passive or active, has a wide range of applications. Aircraft industry, for example, it is interested in using active flow control to modify lift and drag on aircraft wings. Car industry, is aiming to reduce vortex formation on the rear of cars/trucks to diminish drag and therefore reduce fuel consumption. Construction industry has traditionally used passive flow control to minimize or even suppress downstream undesirable vortices on bridges, buildings, pipes placed perpendicular to a flow, etc; the use of active flow control is also currently under study. Several methods have been so far tested to find out its efficiency, reliability and simplicity regarding the active flow control approach. The use of constant blowing, constant suction, periodic blowing and suction, involving devices like synthetic jets or fluidic actuators is nowadays being tested in many fields. Important parameters related to active flow control actuators are, the precise location of the actuation system, the fluid jet amplitude, the momentum coefficient and the jet frequency if pulsating flow is used. In the present paper, the effect of suction and blowing at different inclination angles, groove dimensions and location, as well as several velocity ratios have been evaluated via CFD on a NACA profile under turbulent conditions, Reynolds number 3*106, angle of attack 12o. The results obtained clarify which set of parameters is mend to be the optimum to maximize lift and minimize drag. Some of the results obtained are presented in the figures below.
Eric Suraud
Université Paul Sabatier, France
Title: A fluid dynamics approach to the dynamics of microscopic systems
Biography:
Eric Suraud is distinguished Professor of Physics at Toulouse University in France and Member of Institut Universitaire de France and of European Academy of Sciences and Academia Europaea. He also had several high level responsibilities in the administration of research in France. After a PhD in Paris and a 10 years of activity in nuclear physics, he turned towards electronic dynamics in the mid 1990’s. He has published more than 170 papers in peer review journals and 7 books. He has been invited to more than 130 international conferences and gave many seminars in laboratories all over the world.
Abstract:
Eric Suraud is distinguished Professor of Physics at Toulouse University in France and Member of Institut Universitaire de France and of European Academy of Sciences and Academia Europaea. He also had several high level responsibilities in the administration of research in France. After a PhD in Paris and a 10 years of activity in nuclear physics, he turned towards electronic dynamics in the mid 1990’s. He has published more than 170 papers in peer review journals and 7 books. He has been invited to more than 130 international conferences and gave many seminars in laboratories all over the world.
Kaifu Ye
Naval Academy of Armament, China
Title: Numerical prediction of the integral length scale of isotropic turbulence
Biography:
Kaifu Ye has completed his Master’s in 1995. He is a famous Researcher in the Marine Engineering. He has published more than 15 papers in reputed journals and has been serving as an Editorial Board Member of repute.
Abstract:
As an important parameter of turbulence, the turbulence integral length scale has always been the hotspot of research. Nowadays, the turbulence integral length scale is obtained mostly by experiment. This paper proposed a numerical method: Compute unsteady flow field by LES, from which obtain fluctuation velocity and calculate the turbulence integral length scale based on velocity cross-correlation function. The three subgrid-scale models: DSL, WALE (wall-adapting local eddy viscosity model) and DKET, were analyzed in unsteady flow, time-average flow and turbulence integral length scale. The DSL turned out to have the highest precision. The DSL numerical method was used to predict the turbulence integral length scale of SUBOFF. The results showed that the peak bars of É… are near 20 and 90 degree according to the existence of horse-shoe vortexes of conning tower and stabilizers; the integral lengths at outside radius were lager than those at inside radius because of the diffusion of vortexes. This research can provide a reference for further understanding of low-frequency broadband noise and the establishment of the numerical method of anisotropic turbulence integral length.
Jingwei Jiang
Naval Academy of Armament, China
Title: Hydrodynamic performance prediction of submarine considering fluid-structure interaction via CFD/FEM
Biography:
Jingwei Jiang has completed his Master’s degree in 2013. Currently, he is a PhD student in Naval Academy of Armament. His major is marine propeller design and fluid and structure interaction. He has published more than 10 papers in reputed journals
Abstract:
A numerical prediction method, considering fluid-structure interaction, has been developed to predict and analyze the hydrodynamic performance of submarine, which is based on CFD (Computational Fluid Dynamics) and FEM (Finite Element Modeling) technology. The flow is considered to be uncompressible and viscous. SST k-ω is chosen as the turbulence model for its good precision and efficient computational-time cost, and SIMPLE algorithm is used to solve the coupled equations of pressure and velocity. Meanwhile, FEM is utilized to compute the structure response of the hull according to the unsteady fluid pressure outside, which is gained from the results of CFD. The interaction effect between the fluid flow and the structure is considered as weak coupling. The deformation of the submarine hull is taken into consideration in every iterative procedure instead of after accomplishing the CFD computation, helping to reduce the design time and increase efficiency greatly. Resistance, stress-strain and natural frequency have been gained from this method. The method is validated by comparing the computational result with the engineering estimation data. The numerical prediction method proposed in this paper is effective, reliable and practical, which makes it a suitable tool for the design and analysis of submarine.
Olga V. Mitrofanova
National Nuclear Research University MEPhI, Russia
Title: Studies of the mechanisms of vortex generation in nature and in engineering
Biography:
Olga V Mitrofanova has completed her PhD from Moscow Engineering Physics Institute, Russia and obtained Doctor of Science degree from Russian Research Center, Kurchatov Institute, Moscow, Russia. She is Professor of National Research Nuclear University “MEPhI”, Leading Researcher of RRC at Kurchatov Institute, Chief Researcher of Institute of Metallurgy and Material Science (Russian Academy of Sciences). Fields of her research activity are hydrodynamics of complicated vortex and turbulent flows, simulation of heat and mass transfer in channels of nuclear power installations. She has published more than 170 papers.
Abstract:
The present report focuses on the problems of physical and mathematical modeling of large-scale vortex structures as special objects of study of fluid dynamics. The analysis of physical features and theoretical description of helical and swirl flows has been done. Physical and computational experiments to identify the mechanisms of appearance of large-scale vortex structures in channels of complex geometry under condition of the turbulent flows of conductive and neutral fluids have been carried out. The theoretical aspects concerning the modeling of the processes of vortex generation and accumulation of energy by large-scale vortex structures have been considered to predict accidents in engineering systems and natural disasters. It is shown that the topology of the stable form of helical-vortex formations has a structural similarity depending on the vorticity intensity of the fluid motion. This paper presents the results of studies on the solution of problems of the safety improving of power installations and the prevention of emergency modes arising from acoustic and resonant effects, interdependence of large-scale vortex motion with acoustic effects in hydro-mechanical systems and with magneto-hydrodynamic effects in conductive fluids, conditions of formation of large scale vortex and swirl flows in nuclear power installations (in particular, the phenomenon of spontaneous swirling of a flow and the generation of large-scale vortices in the collector systems of the fast neutron reactors), parameters of acoustic oscillations arising during the generation of stable vortex structures (to prevent the development of vibrations) and phenomena of acoustic cavitation and other mechanisms of mechanical energy transformation in high-speed vortex streams. The obtained results are intended both for engineering applications and for the development of simulation methods to predict some hazardous geophysical processes such as hurricanes, tornados, tsunami and changing the direction of ocean currents.
V V Aristov
RAS - Federal Research Centre “Computer Science and Controlâ€, Russia
Title: Simulations of non equilibrium flows by kinetic methods and non classical effects
Biography:
V V Aristov has completed his PhD from Moscow Institute of Physics and Technology and Post-doctoral studies from Dorodnicyn Computing Centre of Russian Academy of Sciences where he defended his Dr.Sc. thesis. He is Head of Subdivision of Kinetic Theory of Gases in Dorodnicyn Computing Centre of Russian Academy of Sciences and Professor of Moscow Institute of Physics and Technology (State University). He has published more than 35 papers in reputed journals.
Abstract:
New problems with nonequilibrium boundary conditions are formulated and solved on the basis of the Boltzmann and kinetic model equations. These simulations are stimulated by modern interest for understanding strong nonequilibrium processes in open systems. Some generalizations of spatially nonuniform relaxation problems for supersonic and subsonic boundary conditions are considered. Direct methods of solving kinetic equations are used. Anomalous stress and heat transport is obtained and analyzed. A known problem of heat conduction between two plates with different temperatures but with the nonequilibrium condition in one of them (namely, in the left boundary) is studied. Some restrictions were found under which the signs of heat flux and temperature gradients are the same. At the boundary the nonequilibrium ellipsoidal distribution function is accepted with different ratios of the transversal temperatures Tnl and longitudinal temperature Txl (which is fixed). The heat flux qx is constant and positive for all variants and the temperature gradients are also positive. Several experimental tests can be proposed to confirm the mentioned effects. The main problem is to create and maintain boundary nonequilibrium states. This could be resolved e.g. by means of the optic lattices or by means of the magnetic trap. One can discuss possible applications of these anomalous effects. A new problem with the “membrane-like” boundary conditions is formulated and solved. Due to accepting different boundary distributions in velocity space, it is possible to form different spatial distributions of macroscopic parameters. Regions with anomalous transport are obtained. Formulation of this problem for the kinetic equation including chemical reactions is also considered. Possible relations for biological oriented problems are discussed.