Khaled Alhussan

Oblique Shock Waves Interaction in a Non-Steady Three Dimensional Rotating Flow

This paper will explain the numerical analysis and the mapping of the flow in a confined region. In this paper some characteristics of non-steady, compressible, flow are explored, including compression and expansion wave interactions and creation. The results will show a promising achievement, first, to understand the flow structure inside a supersonic confined region, second, to use this knowledge to interpolate the numerical results in order to achieve a design methodology that will benefit the industrial applications for example in turbomachinery. Results including contour plots of static pressure, total pressure, Mach number, temperature and velocity vectors will show the structure of rotating oblique shock waves in a complex three-dimensional conical surface. A CFD analysis enables one to understand the complex flow structure inside this confined region. Through this computational analysis, a better interpretation of the physical phenomenon of the three dimensional rotting oblique shock waves can be achieved. It is essential to evaluate the ability of numerical technique that can solve problems in which compression and expansion waves occur. In particular it is necessary to understand the details of developing a mesh that will allow resolution of some discontinuities in similar flow.© 2005 ASME

Study the Structure of Three Dimensional Oblique Shock Waves Over Conical Rotor-Vane Surfaces

This paper will explain the numerical analysis and the mapping of the flow in a confined region. In this paper some characteristics of non-steady, compressible, flow are explored, including compression and expansion wave interactions and creation. The results will show a promising achievement, first, to understand the flow structure inside a supersonic confined region, second, to use this knowledge to interpolate the numerical results in order to achieve a design methodology that will benefit the industrial applications for example in turbomachinery. Results including contour plots of static pressure, total pressure, and Mach number will show the structure of oblique shock waves in a complex three-dimensional conical surface. A CFD analysis enables one to understand the complex flow structure inside this confined region. Through this computational analysis, a better interpretation of the physical phenomenon of the three dimensional rotting oblique shock waves can be achieved. It is essential to evaluate the ability of numerical technique that can solve problems in which compression and expansion waves occur. In particular it is necessary to understand the details of developing a mesh that will allow resolution of some discontinuities in similar flow.Copyright

The Effect of the Boundary Layer Separation in Y-Junction Shape

The work to be presented herein is a theoretical and numerical analysis of the complex fluid mechanism that occurs inside a Y-junction shape specifically with regard to the boundary layer separation, vortex shedding and generation of wake. The boundary layer separates from the surface forms a free shear layer and is highly unstable. This shear layer will eventually roll into a discrete vortex and detach from the surface. A periodic flow motion will develop in the wake as a result of boundary layer vortices being shed from the solid boundary. The periodic nature of the vortex shedding phenomenon can sometimes lead to unwanted structural vibrations, especially when the shedding frequency matches one of the resonant frequencies of the structure. This paper shows a numerical analysis of boundary layer separation that occurs in an internal flow; the Y-junction shape. This research shows a numerical simulation of mapping the flow inside Y-junction shape flow. The results show that for small divergent angle namely less that 30-degree the flow separation is almost negligible and that downstream, away from the junction, the boundary layer reattaches and normal flow occurs i.e. the effect of the boundary layer separation is only local.Copyright

Detached Shock Waves Analysis

The work to be presented herein is a Computational Fluid Dynamics investigation of the complex fluid phenomena specifically with regard to the structure of detached shock waves over a moving body. This paper will show a relationship between the geometrical data and the strength and position of the detached shock waves, over moving body. The aim of this paper is to develop a relationship between the Mach number, the geometry and the strength of the detached shock wave. A study was completed on a different number of configurations. Results including contour plots of Mach number, static pressure, and static temperature showed the structure of 2-D detached shock waves in a complex region. A CFD analysis enables one to understand the complex flow structure of the detached shock waves over a body with different configurations. The results will show that for η>1 the detached shock will stand at farther distance than η<1 for the same geometrical shape. Through this computational analysis, a better interpretation of the physical phenomenon of the two dimensional detached shock waves can be achieved and to use this knowledge to achieve a design methodology that will benefit the industrial applications.Copyright

Interaction and Reflection of Shock Waves in Three-Dimensional Turbulent Flow

In this paper some characteristics of non-steady, compressible, flow are explored, including compression and expansion waves creation reflection and interaction shock waves. The work to be presented herein is a Computational Fluid Dynamics investigation of the complex fluid phenomena that occur inside 2-D and 3-D regions, specifically with regard to the structure of the oblique shock waves, the reflected shock waves and the interactions of the shock waves. The flow is so complex that there exist oblique shock waves, expansion fans, slip surfaces, and shock wave reflections and interactions. The flow is non-steady, viscous, compressible, and high-speed supersonic. This paper will show a relationship between the Mach numbers and the angles of the reflected shock waves, over a double step, opposed equal wedges, and opposed unequal wedges. The aim of this paper is to study the characteristics of the flow inside 2-D and 3-D regions where creation, reflection and interaction of multiple shock waves.Copyright

Implementation of heterogeneous detonation in a pulsed combustor – PDE model

ABSTRACT This work is devoted to the use of detonative combustion of a liquid fuel in technical devices to obtain a jet thrust. The experimental and theoretical aspects of the organization of detonation in heptane/air/oxygen mixtures are considered. The pulsed regime of detonation at a frequency of 50 Hz has been implemented for the first time in a small-size tube (25 mm in diameter and 740 mm in length). The physical and technical methods that could accelerate the deflagration-to-detonation transition have been studied. The influence of thermal activation of a combustible mixture prior to its ignition and of the special form of a porous obstacle on the magnitude of the predetonation distance is established. The degree of this influence depends on the component composition, equivalence ratio, and the degree of filling the tube with a mixture.

Improvement of Physical-Mechanical Properties of the Composite Materials in Aircraft Structure Using Carbon Nanomaterial Based on Phenolic Binder and Fiberglass

Aggregate stability of “carbon nanotube-polymer matrix” depends on the specific features of Surface tube and surrounding polymer interaction, i.e. The behavior of nanocarbon particles assembly in each particular system. This work is provided with the conditions of used carbon nanomaterial treatment for the improvement of its aggregate stability when introducing into phenolic matrix.Multiwall carbon carbon nanotubes and nanofibers possess unique properties which allow to constantly widen the spheres of their practical application. Recently there have appeared a lot of works dedicated to the creation of composite materials with the improved properties via CNM introduction into various polymers [1, 2].However until the present time it was impossible to fulfill the possibilities of the application of carbon materials as modified additives completely. As carbon nanotubes and nanofibers are very small and possess high surface energy they easily form agglomerates with tens of microns sizes which reduce the efficiency of additive and matrix interaction.Copyright

Transverse Jets Analysis on High Speed Rotating Body of Revolution

This research discusses the transverse jet characteristics issuing from a three dimensional body of revolution into a high speed external flow. This phenomenon creates a complex flow field whose influence on the flow structure is not always easy to predict. In order to investigate the fundamental theory of the transverse jet interaction process, extensive numerical calculations have been conducted in this paper, which has led to the creation of a comprehensive understanding of the structure of the complex flow field. The analysis will show the contour plots of Mach number and the pressure distribution that are function of angle of attack, Reynolds number and the velocity of jet exit. This research demonstrates the creation of bow shock, shock waves interactions, and boundary layer separation and recirculation zone. The results will show that adding a transverse jet will change the flow structure around and behind the body especially with regard to viscous drag and pressure drag, shock waves interactions, boundary layer separations, recirculation and wake.

Numerical Solution of Navier-Stokes Equations for Separating and Reattaching Flow over a Double Steps Expansion and Contraction

This paper shows a numerical solution for Navier-Stokes equations for well known flow phenomenon; the flow separation and the boundary layer reattaching of a double steps expansion and contraction channel. This paper discusses research variables that directly impact the ability to obtain non-circulating flow and techniques to reduce flow separation. This study shows that the separation and the circulation of the flow can be minimized and that is by injecting cross flow (90-degrees) with a magnitude of 0.2 of the inlet velocity.

Multi-Fins Decelerator for Blunt Body in Turbulent Flows

The work to be presented herein is a Computational Fluid Dynamics investigation of the complex fluid mechanisms that occur over blunt body with and without a decelerator, specifically with regard to the total aerodynamic drag. Drag is needed to decelerate the body. The aim of this research is to design deceleration devices for a blunt body. In this paper a qualitative analysis of the flow structure over a blunt body and blunt body with a double fins decelerator was shown. A drag over moving body consists of two components: pressure drag and friction drag. Drag is due to the effect of viscosity. Pressure drag is a result of the eddying motions that are generated in the fluid due to the movement of the body. Pressure drag is related to the cross-sectional area of the body and it is associated with the formation of a wake it is also important for separated flows. Frictional drag is a result of the friction between the fluid and the surfaces over which it is flowing. Frictional drag is related to the surface area exposed to the flow and it is associated with the development of boundary layers it is also important for attached flows. For a blunt body, pressure drag is the dominant source of drag, but for streamlined body friction drag is the dominant source of air resistance. In some applications of aerodynamics, a deceleration of a moving body is required therefore the prediction and controlling of the drag is essential. The deceleration devices such as air bag or fins can be added to the body to increase the aerodynamics drag. For a supersonic speed, a flow around blunt body is complicated due to the detached shock wave, flow separation, boundary layer and their interactions. When a decelerator is integrated with the blunt body the flow is subject to sever change of aerodynamic forces and velocity. The results will show, that the adding a deceleration device will change the flow structure behind the body especially with regard to the pressure drag and wake. Results of contour plots of static pressure, static temperature, and Mach number for zero angles of attack will demonstrate that the aerodynamic forces and the velocity are changed when the deceleration device is integrated with the blunt body.