Day 2 :
Keynote Forum
Ian R McAndrew
Capitol Technology University, USA
Keynote: Aerodynamic implications for twin-wing aircraft at high altitudes
Time : 09:05-09:45
Biography:
Ian R McAndrew has been working and researching in several universities for over 27 years and supervising PhD students since the late 1990s. He is a Conference Chair on several international conferences and is frequently asked to deliver Keynote speeches every year all over the world. He is also the Editor of two international journals, Associate Editor for several more and have 57 peer reviewed journals and conference papers. He is also a Fellow of the Royal Aeronautical Society and Associate Dean of Research for Embry Riddle Aeronautical University.
Abstract:
Twin-wing designs offer many aerodynamic advantages and in particular, lower speeds before stall. As unmanned aerial vehicles (UAV) are used for more applications they are still limited under international law to be limited for staying within line-of-visual- sight (LOVS). NEXTGEN is investigating if they can be integrated into commercial airspace. This research discusses and demonstrates that a twin-wing design can be used for high altitude flight at lower speeds when piloted as an unmanned aerial vehicle as it removes the problems associated with design constraints. Without a pilot the negative stagger, upper wing off-set towards the front can be changed to a positive stagger, vertically behind the lower wing. Previous research by the authors have shown that under specific angles of attack (AoA), sufficient combined lift is possible for flight above commercial airspace and at low speeds, which allow for low technology power units to still be used. The conclusions show that sufficient lift without major drag additions is a feasible and warrants further detailed investigations.
Keynote Forum
Igor Palymskiy
Siberian State University of Telecommunications and Information Sciences, Russia
Keynote: About convection stability of the gas-vapor mixture at the temperature close to critical
Time : 09:45-10:25
Biography:
Igor Palymskiy completed his Doctor of Science in the year 2012 from Perm University. Now he is the Professor of Physics Department of Siberian State University of Telecommunications and Information Sciences, Novosibirsk city, Russia. He has published more than 80 papers in reputed journals. He is expertise in area of numerical methods, convection of homogeneous media and gas with chemical reactions.
Abstract:
The intensive investigations of convection modes in the homogeneous gas have been performed. However, the condensation and evaporation of liquid often accompany the moving of gas. The amount of the liquid in the vapor state is defined by saturated vapor pressure. The last comparatively quickly grows with the temperature increasing at growing density of the gas. The gas is considered to be ideal so after evaporation of the whole liquid (the critical point) density gas falls off with growing of the temperature. In the critical point the heat expansion coefficient has the change of its sign. The convection of the oxygen O2 with liquid-vapor cyclohexane C6H12 mixture is considered in a horizontal layer at heating from below, it is supposed that the cyclohexane condensation occurs on the horizontal isothermal boundaries and that the partial pressure of the oxygen is to be constant. The layer is divided into two sublayers by critical temperature moreover the temperature of the lower horizontal boundary is above critical and upper boundary - below. For study of convection stability the Galerkin method is applied. It is shown that at sufficient value of Rayleigh number the convective instability may be observed in unstable lower sublayer. At decreasing of the relative thickness of the unstable lower layer τ the level of convective instability decreases and vice versa. The asymptotic behave of neutral curve, position of the instability boundary on the wave plane, critical Rayleigh number and corresponding critical wave number, the increment of most dangerous disturbance is investigated at parameter τ close to 1 and 0. The asymptotes at τ close to 0 are derived numerically and at τ close to 1 - analytically as expansion in powers of (1- τ)3.
- Aerodynamics | Biofluid Mechanics | Fluid Flow | Turbomachinery | Thermo-Fluid Dynamics | Numerical Methods
Location: Sylt 3
Chair
Ian R McAndrew
Capitol Technology University, USA
Co-Chair
Igor Palymskiy
Siberian State University of Telecommunications and Information Sciences, Russia
Session Introduction
M A Mochalov
Russian Federal Nuclear Center, Russia
Title: Quasi-isentropic compressibility of deuterium at pressure region of ~12 Трa
Time : 10:25-10:50
Biography:
M A Mochalov has the ScD degree in Physics and Mathematics. He is a high-quality expert in experimental investigations of thermal physical properties for plasma of cryogenic liquids (such as nitrogen, argon, krypton, and xenon), gaseous helium and deuterium at shock compression and quasi-isentropic compression in the megabar range of pressures. His obtained data are well-known in Russia and other countries. The data are unique and correspond to the world level of investigations in physics of high energy densities.
Abstract:
We report on the experimental results on the quasi-isentropic compressibility of a strongly non-ideal deuterium plasma compressed to the density ρ≈10 g/cc by pressure Ð =11400 GPa (114 Mbar) on a setup of spherical geometry. We describe the characteristics of the experimental setup, as well as the methods for the diagnostics and interpretation of the experimental results. The trajectory of metal shells that compress the deuterium plasma was detected using powerful pulsed X-ray sources with maximal electron energy of up to 60 MeV. The value of the plasma density ρ≈10 g/cc was determined from the measured value of the shell radius at the instant that it was stopped. The pressure of the compressed plasma was determined using gas dynamic calculations taking into account the actual characteristics of the experimental setup. In the laboratory experiment on multiple shock loading of gaseous deuterium was achieved the state, very close to that of planet-giants of the solar system, e.g. Jupiter and Saturn.
Tahir Yavuz
Baskent University, Turkey
Title: Design of the concentrator – wind turbine combinations
Time : 11:10-11:35
Biography:
Tahir Yavuz academic career ; BSc in Mechanical Engineering, Karadeniz Technical Univ. Turkey, PhD in Aeronoutical Engineering, Leicester University, England. Worked at Erciyes and Karadeniz Technical Universities, Turkey. Currently working as a full time professor at Baskent University, Turkey. Interested in bluff body aerodynamics, renewable energies such as wind energies and wind turbines. Developed a high performance wind turbine blades such as airfoil with slatt arrangements.
Abstract:
Wind technology is one of the fastest growing alternative energy technologies. This technology can also be used in hydrokinetic turbines. Today, depending on technological developments, the minimum speed of wind and hydrokinetic current to produce electricity from wind and hydrokinetic turbines is about 3-4 m/s and 1-2 m/s respectively. These limit the choice of physical locations where wind and hydrokinetic turbines can be implemented. To generate electricity at lower wind speed and hydrokinetic current the concentrator augmented wind turbine (CAWT) is considered. The CAWT improves the efficiency of the wind turbines by increasing the wind speed upstream of the turbine. Preliminary work of the study was presented in the 2nd International Conference on Fluid Dynamics & Aerodynamics. In this study, the optimization of the combinations of concentrator with wind turbine is curried out. The actuator porous disc model is used to represent wind turbine in the concentrator. The Box-Behnken experimental method combining the CFD analysis is used in the optimization. Optimum concentrator parameters are determined by the means of the Response Surface Method. The optimum geometric parameters are obtained as a function of the turbine diameter. Concentrator increases the free wind speed and power output by the factors of about 1.38 and 2.62 respectively. The system can be used offshore and onshore wind turbine applications.
Anouchah Latifi
Qom University of Technology, Iran
Title: Wind wave generation in finite depth
Time : 11:35-12:00
Biography:
Anouchah Latifi completed his PhD in the year 1991 from Montpellier University-France. After passing several years in reputed institutions in USA, Belgium, France and many other countries, he is now attached to the Qom University of Technology in Iran and is the Founder and Organizer of the yearly Iranian Mathematical Physics Conferences. He is expertise in nonlinear coupled waves, nonlinear evolution equations and integrability. He has also many activities in solar energy and environmental projects.
Abstract:
In this work, we present the extension of the Miles’ and Jeffreys’ theories of the wind wave generation to finite depth through three different approaches; linear approach, quasi-linear approach and fully nonlinear approach. In the first case, the dispersion relation provides a depth dependent wave growth rate providing a good agreement with the data from the Australian shallow water experiment as well as the data from the Lake George experiment. In the second case, the evolution of wind waves in finite depth is reduced to an anti-dissipative Korteweg-de Vries-Burgers equation, and its solitary wave solution is exhibited presenting blow up and breaking in finite time. Finally, in the third case, the full nonlinear Green-Naghdi model equation is derived and two families of growth rate and their allowed minimum and maximum values are exhibited.
Amal Kraiem
University of Sfax, Tunisia
Title: Rheological proprieties of bitumen: experimental squeeze flow test
Time : 12:00-12:25
Biography:
Amal Kraiem has obtained her Electromechanical Engineering Diploma in 2014. Currently she is a PhD student at the unit of Computational Fluid Dynamic and Transfer Phenomena (CFDTP) in the Department of Mechanics at the National Engineering School of Sfax, Tunisia under the supervision of Prof. Abdelhak Ayadi. She has participated in one international and one national conference. She taught courses at the National Engineering School of Sfax, Tunisia.
Abstract:
The squeeze flow tests were studied by many authors to measure the rheological properties of fluids. In the present work, experimental squeezing flow test with constant area between two parallel disks of bitumen has been investigated. The effect of the temperature, the process of preparing the sample and the gap between the discs were discussed. The obtained results were compared with the theoretical models. The behavior of bitumen depends on the ambient temperature thus, for a high temperature the consistency decreases. Also the effect of viscosity and the yield stress required for the compression test. Finally, a power law model and a biviscous fluid are used to describe the rheological behavior of the squeezing flow of pure bitumen.
Hela Krir
University of Sfax, Tunisia
Title: Extrudate swell under the effect of radial flow and intrinsic factors to the polymer upstream the die
Time : 12:25-12:50
Biography:
Hela Krir has obtained her Materials Engineering diploma in 2016. Actually, she is a PhD student at the unit of Computational Fluid Dynamics and Transfer Phenomena in the Department of Mechanics at the National Engineering School of Sfax, Tunisia under the supervision of Prof. Abdelhahak Ayadi and Prof. Chedly Bradaii.
Abstract:
It is well known that extrusion is a process that allows polymer melts to be shaped. However, various defects and flow instabilities occur not only to mitigate the production rates but also to influence the appearance and the quality of extrudate products. The influence of intrinsic factors, elastic energy and memory effect, and radial flow on the appearance and the evolution of the extrudate swelling are investigated in the present work. The experiments have been performed with linear polydimethylsiloxane (PDMS) via a capillary rheometer in which a convergent radial flow was created upstream the contraction. The correspondence between the effects of radial flow, entry elastic stored energy and memory effect is discussed. In particular, as the influence of the considered radial flow, extrudate photographs showed that when the gap ratio is reduced, the extrudate swell is lessened than what it is when radial flow geometry is not installed. Moreover, with a narrower gap, the polymer stores less energy during its passage through the die which implies a lower extrudate swelling at the outlet of the die. Results previously mentioned may be related both to shear and elongational components of radial flow.