yasser Gamiel | Tanta University (original) (raw)
Papers by yasser Gamiel
Case Studies in Thermal Engineering, 2021
Applied Thermal Engineering, 2021
Abstract In the current research, we introduced a new concept of free water dripping on the basin... more Abstract In the current research, we introduced a new concept of free water dripping on the basin water using cracks in the suspended trays of the trays solar still to break the boundary layers and surface tension of the basin water inside the trays solar distiller. This new technique would lead to improve the productivity of the solar still and reduce the cost of production water. The previous publications concerned with breaking the surface tension of basin water such as using fan, blades, forced water dripping and air bubbles inside the water depended on using traditional sources of energy, which have a negative effect on the cost of the distilled water. As a result, the effect of creating cracks in the trays surface on the performance of trays solar still was investigated. Besides, the influence of different numbers of cracks such as 7, 10, and 14 cracks was studied. For further improvement of trays still performance, internal and external reflectors were employed onto the trays still and tested. The experimental results obtained that the number of 10 cracks provided greater productivity compared to that obtained when using either 7 or 14 cracks, where the productivity was enhanced by 12%, 9%, and 8% at 10, 7, and 14 cracks, respectively. At 7 cracks, the total distillates of the reference still and trays still with internal and external mirrors were 2450 and 5000 mL/m2·day, respectively with an enhancement percentage of 104%. Furthermore, the highest efficiency was obtained for the trays still with internal and external mirrors at 7 cracks, where it was 51% compared to 34.5% for the traditional distiller. The estimated average costs of one liter of fresh water for CSS and TSS are 0.033 and 0.021 $/L, respectively.
Journal of Engineering Research
Alexandria Engineering Journal, 2022
Theoretical and Mathematical Physics, 2017
We study the linear stability of a three-layer flow of immiscible liquids located in a periodic n... more We study the linear stability of a three-layer flow of immiscible liquids located in a periodic normal electric field. We consider certain porous media assumed to be uniform, homogeneous, and isotropic. We analytically and numerically simulate the system of linear evolution equations of such a medium. The linearized problem leads to a system of two Mathieu equations with complex coefficients of the damping terms. We study the effects of the streaming velocity, permeability of the porous medium, and the electrical properties of the flow of a thin layer (film) of liquid on the flow instability. We consider several special cases of such systems. As a special case, we consider a uniform electric field and solve the transition curve equations up to the second order in a small dimensionless parameter. We show that the dielectric constant ratio and also the electric field play a destabilizing role in the stability criteria, while the porosity has a dual effect on the wave motion. In the case of an alternating electric field and a periodic velocity, we use the method of multiple time scales to calculate approximate solutions and analyze the stability criteria in the nonresonance and resonance cases; we also obtain transition curves in these cases. We show that an increase in the velocity and the electric field promote oscillations and hence have a destabilizing effect.
Springer Proceedings in Mathematics & Statistics, 2021
Alexandria Engineering Journal
Teoreticheskaya i Matematicheskaya Fizika
International Journal of Mathematics Trends and Technology, 2017
International Journal of Non-Linear Mechanics, 2013
ABSTRACT The present work deals with temporal stability properties of a falling liquid film down ... more ABSTRACT The present work deals with temporal stability properties of a falling liquid film down an inclined plane in the presence of constant electromagnetic field. Using the Kármán approximation, the problem is reduced to the study of the evolution equation for the free surface of the liquid film derived through a long-wave approximation. A linear stability analysis of the base flow is performed. Also, the solutions of stationary waves and Shkadov waves are introduced and discussed analytically by analyzing the linearized instability of the fixed points and Hopf bifurcation.
ABSTRACT The present work deals with temporal stability properties of a falling liquid film down ... more ABSTRACT The present work deals with temporal stability properties of a falling liquid film down an inclined plane in the presence of a parallel subsonic gas flow. The waves are described by evolution equation previously derived as a generalization of the model for the Newtonian liquid. We confirm linear stability results of the basic flow using the Orr–Sommerfeld analysis to that obtained by long wave approximation analysis. The non-linear stability criteria of the model are discussed analytically and stability branches are obtained. Finally, the solitary wave solutions at the liquid–gas interface are discussed, using specially envelope transform and direct ansatz approach to Ginzburg–Landau equation. The influence of different parameters governing the flow on the stability behavior of the system is discussed in detail.
European Journal of Mechanics - B/Fluids, 2010
The present work deals with the stability properties of an immersed annulus swirling jet in a zer... more The present work deals with the stability properties of an immersed annulus swirling jet in a zero gravity environment. The considered system is composed of two streaming coaxial fluid cylinders, embedded in a third streaming fluid, where the intermediate one (annulus) has a uniform swirl speed. The fluids are immiscible, inviscid, and incompressible. The linear stability criteria of the model are discussed analytically and stability diagrams are obtained. We conclude that the radii ratio, the Weber number and the swirl number play a significant role in determining the dynamics of the developing interfacial patterns.
Acta Mechanica Sinica, 2012
The present work discusses both the linear and nonlinear stability conditions of a viscous fallin... more The present work discusses both the linear and nonlinear stability conditions of a viscous falling film down the outer surface of a solid vertical cylinder which moves in the direction of its axis with a constant velocity. After studying the linear conditions, a generalized nonlinear kinematic model is then derived to present the physical system. Applying the boundary conditions, analytical solutions are obtained using the long-wave perturbation method. In the first step, the normal mode method is used to characterize the linear behaviors. In the second step, the nonlinear film flow model is solved by using the method of multiple scales, to obtain Ginzburg-Landau equation. The influence of some physical parameters is discussed in both linear and nonlinear steps of the problem, and the results are displayed in many plots showing the stability criteria in various parameter planes.
Acta Mechanica Sinica, 2012
The present work discusses both the linear and nonlinear stability conditions of a viscous fallin... more The present work discusses both the linear and nonlinear stability conditions of a viscous falling film down the outer surface of a solid vertical cylinder which moves in the direction of its axis with a constant velocity. After studying the linear conditions, a generalized nonlinear kinematic model is then derived to present the physical system. Applying the boundary conditions, analytical solutions are obtained using the long-wave perturbation method. In the first step, the normal mode method is used to characterize the linear behaviors. In the second step, the nonlinear film flow model is solved by using the method of multiple scales, to obtain Ginzburg-Landau equation. The influence of some physical parameters is discussed in both linear and nonlinear steps of the problem, and the results are displayed in many plots showing the stability criteria in various parameter planes.
Case Studies in Thermal Engineering, 2021
Applied Thermal Engineering, 2021
Abstract In the current research, we introduced a new concept of free water dripping on the basin... more Abstract In the current research, we introduced a new concept of free water dripping on the basin water using cracks in the suspended trays of the trays solar still to break the boundary layers and surface tension of the basin water inside the trays solar distiller. This new technique would lead to improve the productivity of the solar still and reduce the cost of production water. The previous publications concerned with breaking the surface tension of basin water such as using fan, blades, forced water dripping and air bubbles inside the water depended on using traditional sources of energy, which have a negative effect on the cost of the distilled water. As a result, the effect of creating cracks in the trays surface on the performance of trays solar still was investigated. Besides, the influence of different numbers of cracks such as 7, 10, and 14 cracks was studied. For further improvement of trays still performance, internal and external reflectors were employed onto the trays still and tested. The experimental results obtained that the number of 10 cracks provided greater productivity compared to that obtained when using either 7 or 14 cracks, where the productivity was enhanced by 12%, 9%, and 8% at 10, 7, and 14 cracks, respectively. At 7 cracks, the total distillates of the reference still and trays still with internal and external mirrors were 2450 and 5000 mL/m2·day, respectively with an enhancement percentage of 104%. Furthermore, the highest efficiency was obtained for the trays still with internal and external mirrors at 7 cracks, where it was 51% compared to 34.5% for the traditional distiller. The estimated average costs of one liter of fresh water for CSS and TSS are 0.033 and 0.021 $/L, respectively.
Journal of Engineering Research
Alexandria Engineering Journal, 2022
Theoretical and Mathematical Physics, 2017
We study the linear stability of a three-layer flow of immiscible liquids located in a periodic n... more We study the linear stability of a three-layer flow of immiscible liquids located in a periodic normal electric field. We consider certain porous media assumed to be uniform, homogeneous, and isotropic. We analytically and numerically simulate the system of linear evolution equations of such a medium. The linearized problem leads to a system of two Mathieu equations with complex coefficients of the damping terms. We study the effects of the streaming velocity, permeability of the porous medium, and the electrical properties of the flow of a thin layer (film) of liquid on the flow instability. We consider several special cases of such systems. As a special case, we consider a uniform electric field and solve the transition curve equations up to the second order in a small dimensionless parameter. We show that the dielectric constant ratio and also the electric field play a destabilizing role in the stability criteria, while the porosity has a dual effect on the wave motion. In the case of an alternating electric field and a periodic velocity, we use the method of multiple time scales to calculate approximate solutions and analyze the stability criteria in the nonresonance and resonance cases; we also obtain transition curves in these cases. We show that an increase in the velocity and the electric field promote oscillations and hence have a destabilizing effect.
Springer Proceedings in Mathematics & Statistics, 2021
Alexandria Engineering Journal
Teoreticheskaya i Matematicheskaya Fizika
International Journal of Mathematics Trends and Technology, 2017
International Journal of Non-Linear Mechanics, 2013
ABSTRACT The present work deals with temporal stability properties of a falling liquid film down ... more ABSTRACT The present work deals with temporal stability properties of a falling liquid film down an inclined plane in the presence of constant electromagnetic field. Using the Kármán approximation, the problem is reduced to the study of the evolution equation for the free surface of the liquid film derived through a long-wave approximation. A linear stability analysis of the base flow is performed. Also, the solutions of stationary waves and Shkadov waves are introduced and discussed analytically by analyzing the linearized instability of the fixed points and Hopf bifurcation.
ABSTRACT The present work deals with temporal stability properties of a falling liquid film down ... more ABSTRACT The present work deals with temporal stability properties of a falling liquid film down an inclined plane in the presence of a parallel subsonic gas flow. The waves are described by evolution equation previously derived as a generalization of the model for the Newtonian liquid. We confirm linear stability results of the basic flow using the Orr–Sommerfeld analysis to that obtained by long wave approximation analysis. The non-linear stability criteria of the model are discussed analytically and stability branches are obtained. Finally, the solitary wave solutions at the liquid–gas interface are discussed, using specially envelope transform and direct ansatz approach to Ginzburg–Landau equation. The influence of different parameters governing the flow on the stability behavior of the system is discussed in detail.
European Journal of Mechanics - B/Fluids, 2010
The present work deals with the stability properties of an immersed annulus swirling jet in a zer... more The present work deals with the stability properties of an immersed annulus swirling jet in a zero gravity environment. The considered system is composed of two streaming coaxial fluid cylinders, embedded in a third streaming fluid, where the intermediate one (annulus) has a uniform swirl speed. The fluids are immiscible, inviscid, and incompressible. The linear stability criteria of the model are discussed analytically and stability diagrams are obtained. We conclude that the radii ratio, the Weber number and the swirl number play a significant role in determining the dynamics of the developing interfacial patterns.
Acta Mechanica Sinica, 2012
The present work discusses both the linear and nonlinear stability conditions of a viscous fallin... more The present work discusses both the linear and nonlinear stability conditions of a viscous falling film down the outer surface of a solid vertical cylinder which moves in the direction of its axis with a constant velocity. After studying the linear conditions, a generalized nonlinear kinematic model is then derived to present the physical system. Applying the boundary conditions, analytical solutions are obtained using the long-wave perturbation method. In the first step, the normal mode method is used to characterize the linear behaviors. In the second step, the nonlinear film flow model is solved by using the method of multiple scales, to obtain Ginzburg-Landau equation. The influence of some physical parameters is discussed in both linear and nonlinear steps of the problem, and the results are displayed in many plots showing the stability criteria in various parameter planes.
Acta Mechanica Sinica, 2012
The present work discusses both the linear and nonlinear stability conditions of a viscous fallin... more The present work discusses both the linear and nonlinear stability conditions of a viscous falling film down the outer surface of a solid vertical cylinder which moves in the direction of its axis with a constant velocity. After studying the linear conditions, a generalized nonlinear kinematic model is then derived to present the physical system. Applying the boundary conditions, analytical solutions are obtained using the long-wave perturbation method. In the first step, the normal mode method is used to characterize the linear behaviors. In the second step, the nonlinear film flow model is solved by using the method of multiple scales, to obtain Ginzburg-Landau equation. The influence of some physical parameters is discussed in both linear and nonlinear steps of the problem, and the results are displayed in many plots showing the stability criteria in various parameter planes.