Samuel Musong | University of Texas at San Antonio (original) (raw)

Papers by Samuel Musong

Research paper thumbnail of Comparison Between The Analytical And Finite Elements Methods For Temperature Field Calculations In Surface Laser Treated Materials

AIP Conference Proceedings, 2007

Research paper thumbnail of A Comparison Between Analytical and the Finite Element Numerical Approach in Determining Shaft Stresses under Various Load Configurations

Research paper thumbnail of A three dimensional immersed boundary-based method for the free and combined convective heat transfer from spherical bodies

Research paper thumbnail of The Effect of Closure Laws on the Simulation Results of Two-Fluid Model of Gas-Solid Flows

Volume 7A: Fluids Engineering Systems and Technologies, 2015

Research paper thumbnail of The Effect of Model Parameters of the Soft-Sphere Scheme on Particle-Particle Collisions

Eulerian and Lagrangian systems need a scheme to model particle-particle or particle-wall collisi... more Eulerian and Lagrangian systems need a scheme to model particle-particle or particle-wall collisions. The soft-sphere scheme is the most common. How do we choose the spring stiffness and damping coefficient in a soft-sphere collision model? How do the collision parameters affect the particle dynamics when particles collide?

Research paper thumbnail of Mixed convective heat transfer from a heated sphere at an arbitrary incident flow angle in laminar flows

The mixed convection from a heated sphere for an arbitrary flow incident angle (h) at low to mode... more The mixed convection from a heated sphere for an arbitrary flow incident angle (h) at low to moderate Reynolds numbers (1 6 Re 6 100) and Richardson numbers (0 6 Ri 6 5) is studied by an immersed boundary method, thereby investigating the influence of different flow incident angles (0 6 h 6 180 ) on the buoyancy flow and heat transfer. The numerical method is validated by comparing the results with the simulation results of pure forced convection as well as those of mixed convection with assisting flow (0°flow incident angle) published in the literature. Extensive simulations for a wide range of different incident flow angles have been performed. New correlations are obtained for the overall Nusselt number (Nu) in terms of h, Ri, and Re, showing a quadratic decrease in Nu with respect to h only for 0 6 h 6 90 (aiding and cross flow) and a half bell-shaped decrease in Nu for 90 < h 6 180 (opposed flow). The combined treatment of mixed convection for the completely upward flow, cross flow, and completely downward flow (i.e. at incident angle 0°, 90°and 180°, respectively) was achieved showing almost linear relationships between the heat transfer rates and Ri for Ri P 1.

Research paper thumbnail of Mixed convective heat transfer from a heated sphere at an arbitrary incident flow angle in laminar flows

The mixed convection from a heated sphere for an arbitrary flow incident angle (h) at low to mode... more The mixed convection from a heated sphere for an arbitrary flow incident angle (h) at low to moderate Reynolds numbers (1 6 Re 6 100) and Richardson numbers (0 6 Ri 6 5) is studied by an immersed boundary method, thereby investigating the influence of different flow incident angles (0 6 h 6 180 ) on the buoyancy flow and heat transfer. The numerical method is validated by comparing the results with the simulation results of pure forced convection as well as those of mixed convection with assisting flow (0°flow incident angle) published in the literature. Extensive simulations for a wide range of different incident flow angles have been performed. New correlations are obtained for the overall Nusselt number (Nu) in terms of h, Ri, and Re, showing a quadratic decrease in Nu with respect to h only for 0 6 h 6 90 (aiding and cross flow) and a half bell-shaped decrease in Nu for 90 < h 6 180 (opposed flow). The combined treatment of mixed convection for the completely upward flow, cross flow, and completely downward flow (i.e. at incident angle 0°, 90°and 180°, respectively) was achieved showing almost linear relationships between the heat transfer rates and Ri for Ri P 1.

Research paper thumbnail of A Three Dimensional Immersed Boundary Method for Free Convection From Single Spheres and Aggregates

A novel numerical technique that utilizes a three-dimensional Immersed Boundary Method (IBM) to s... more A novel numerical technique that utilizes a three-dimensional Immersed Boundary Method (IBM) to solve the thermal interactions between spherical particles in a fluid is developed. At first, the natural convection of an isolated isothermal sphere immersed in a viscous fluid is analyzed and a new correlation for the heat transfer rate from a single sphere is obtained for 0.5≤Pr≤200 and 0 ≤ Gr ≤500. Secondly, the free convection heat transfer rate of a pair of spheres (bi-sphere) and spherical clusters immersed in air (Pr=0.72) were investigated using this numerical technique. The interactions depend on the separation distance between the spheres. It was observed that an increase in the separation of two spheres in tandem or side-by-side within a certain range may enhance the average heat transfer rate, when the interparticle distance is more than five radii. The average heat transfer rate of a cluster of touching, identical spheres with the same Grashof number was found to decrease as the number of spheres increased in the cluster.

Research paper thumbnail of Effects of Rod Shapes on the Drag Force of Particles in a Shear Flow

The understanding of its shape on the movement of microparticles and nanoparticles is crucial to ... more The understanding of its shape on the movement of microparticles and nanoparticles is crucial to the development of technologies of using these particles in drug delivery systems. The effect of shape on nanoparticles used in drug delivery, in particular, is a very active area of experimental investigation. Also, the determination of the drag force on nanoparticles of different shapes is very important in designing effective nanoparticle-mediated therapies. One of the common shapes of nanoparticles is rod. In this study we present a resolved discrete particle method (RDPM), which is also called the Direct Numerical Simulation (DNS), to investigate the effect of rod shapes on the drag force in a vicious fluid as compared to other particle shapes such as a sphere and a cone. These particles are assigned the same volume and placed in contact with the bottom wall in a simple shear flow. Their drag forces are computed numerically; it is found that the particle shape has a significant effect on the drag forces. In the case of a spherical particle, our results agree very well with the analytical results found in the literature. The drag force on a rod at different orientations and the motion of two rod-shaped particles of identical volume are in a shear flow are also examined. The motion of a rod-shaped particle and a cone-shaped particle in a shear flow at low Reynolds number is also compared.

Research paper thumbnail of Mixed convective heat transfer from a heated sphere at an arbitrary incident flow angle in laminar flows

The mixed convection from a heated sphere for an arbitrary flow incident angle (h) at low to mode... more The mixed convection from a heated sphere for an arbitrary flow incident angle (h) at low to moderate Reynolds numbers (1 6 Re 6 100) and Richardson numbers (0 6 Ri 6 5) is studied by an immersed boundary method, thereby investigating the influence of different flow incident angles (0 6 h 6 180 ) on the buoyancy flow and heat transfer. The numerical method is validated by comparing the results with the simulation results of pure forced convection as well as those of mixed convection with assisting flow (0°flow incident angle) published in the literature. Extensive simulations for a wide range of different incident flow angles have been performed. New correlations are obtained for the overall Nusselt number (Nu) in terms of h, Ri, and Re, showing a quadratic decrease in Nu with respect to h only for 0 6 h 6 90 (aiding and cross flow) and a half bell-shaped decrease in Nu for 90 < h 6 180 (opposed flow). The combined treatment of mixed convection for the completely upward flow, cross flow, and completely downward flow (i.e. at incident angle 0°, 90°and 180°, respectively) was achieved showing almost linear relationships between the heat transfer rates and Ri for Ri P 1.

Research paper thumbnail of Direct numerical simulation of heat and mass transfer of spheres in a fluidized bed

We have developed a direct numerical simulation approach combined with the immersed boundary (DNS... more We have developed a direct numerical simulation approach combined with the immersed boundary (DNS-IB) method for studying heat transfer in particulate flows. In this method, fluid velocity and temperature fields are obtained by solving the modified momentum and heat transfer equations, which are due to the presence of heated particles in the fluid; particles are tracked individually and their velocities and positions are solved based on the equations of linear and angular motions; particle temperature is assumed to be constant. The momentum and heat exchanges between a particle and the surrounding fluid at its surface are resolved using the immersed boundary method with the direct forcing scheme. The DNS-IB method has been used to study the heat transfer of 225 heated spheres in a fluidized bed. By exploring the rich data generated from the DNS-IB simulations, we are able to obtain statistically averaged fluid and particle velocities as well as the overall heat transfer rate in the fluidized bed. Good agreement between the current study and the one by is found for the hydrodynamic properties of the bed such as pressure gradients within the bed and the relationship between fluidization velocity and bed solid fraction. The particle-averaged Nusselt number is found to increase as the fluidization velocity increases and the bed height rises; particles at the entrance of the bed tend to have the maximum heat transfer rate because of the higher particle-fluid temperature gradients in this region; as the fluid moves upward in the bed, it gets warmer, which reduces particle-fluid temperature gradients and decreases the transfer rate of particles.

Research paper thumbnail of Comparison Between The Analytical And Finite Elements Methods For Temperature Field Calculations In Surface Laser Treated Materials

AIP Conference Proceedings, 2007

Research paper thumbnail of A Comparison Between Analytical and the Finite Element Numerical Approach in Determining Shaft Stresses under Various Load Configurations

Research paper thumbnail of A three dimensional immersed boundary-based method for the free and combined convective heat transfer from spherical bodies

Research paper thumbnail of The Effect of Closure Laws on the Simulation Results of Two-Fluid Model of Gas-Solid Flows

Volume 7A: Fluids Engineering Systems and Technologies, 2015

Research paper thumbnail of The Effect of Model Parameters of the Soft-Sphere Scheme on Particle-Particle Collisions

Eulerian and Lagrangian systems need a scheme to model particle-particle or particle-wall collisi... more Eulerian and Lagrangian systems need a scheme to model particle-particle or particle-wall collisions. The soft-sphere scheme is the most common. How do we choose the spring stiffness and damping coefficient in a soft-sphere collision model? How do the collision parameters affect the particle dynamics when particles collide?

Research paper thumbnail of Mixed convective heat transfer from a heated sphere at an arbitrary incident flow angle in laminar flows

The mixed convection from a heated sphere for an arbitrary flow incident angle (h) at low to mode... more The mixed convection from a heated sphere for an arbitrary flow incident angle (h) at low to moderate Reynolds numbers (1 6 Re 6 100) and Richardson numbers (0 6 Ri 6 5) is studied by an immersed boundary method, thereby investigating the influence of different flow incident angles (0 6 h 6 180 ) on the buoyancy flow and heat transfer. The numerical method is validated by comparing the results with the simulation results of pure forced convection as well as those of mixed convection with assisting flow (0°flow incident angle) published in the literature. Extensive simulations for a wide range of different incident flow angles have been performed. New correlations are obtained for the overall Nusselt number (Nu) in terms of h, Ri, and Re, showing a quadratic decrease in Nu with respect to h only for 0 6 h 6 90 (aiding and cross flow) and a half bell-shaped decrease in Nu for 90 < h 6 180 (opposed flow). The combined treatment of mixed convection for the completely upward flow, cross flow, and completely downward flow (i.e. at incident angle 0°, 90°and 180°, respectively) was achieved showing almost linear relationships between the heat transfer rates and Ri for Ri P 1.

Research paper thumbnail of Mixed convective heat transfer from a heated sphere at an arbitrary incident flow angle in laminar flows

The mixed convection from a heated sphere for an arbitrary flow incident angle (h) at low to mode... more The mixed convection from a heated sphere for an arbitrary flow incident angle (h) at low to moderate Reynolds numbers (1 6 Re 6 100) and Richardson numbers (0 6 Ri 6 5) is studied by an immersed boundary method, thereby investigating the influence of different flow incident angles (0 6 h 6 180 ) on the buoyancy flow and heat transfer. The numerical method is validated by comparing the results with the simulation results of pure forced convection as well as those of mixed convection with assisting flow (0°flow incident angle) published in the literature. Extensive simulations for a wide range of different incident flow angles have been performed. New correlations are obtained for the overall Nusselt number (Nu) in terms of h, Ri, and Re, showing a quadratic decrease in Nu with respect to h only for 0 6 h 6 90 (aiding and cross flow) and a half bell-shaped decrease in Nu for 90 < h 6 180 (opposed flow). The combined treatment of mixed convection for the completely upward flow, cross flow, and completely downward flow (i.e. at incident angle 0°, 90°and 180°, respectively) was achieved showing almost linear relationships between the heat transfer rates and Ri for Ri P 1.

Research paper thumbnail of A Three Dimensional Immersed Boundary Method for Free Convection From Single Spheres and Aggregates

A novel numerical technique that utilizes a three-dimensional Immersed Boundary Method (IBM) to s... more A novel numerical technique that utilizes a three-dimensional Immersed Boundary Method (IBM) to solve the thermal interactions between spherical particles in a fluid is developed. At first, the natural convection of an isolated isothermal sphere immersed in a viscous fluid is analyzed and a new correlation for the heat transfer rate from a single sphere is obtained for 0.5≤Pr≤200 and 0 ≤ Gr ≤500. Secondly, the free convection heat transfer rate of a pair of spheres (bi-sphere) and spherical clusters immersed in air (Pr=0.72) were investigated using this numerical technique. The interactions depend on the separation distance between the spheres. It was observed that an increase in the separation of two spheres in tandem or side-by-side within a certain range may enhance the average heat transfer rate, when the interparticle distance is more than five radii. The average heat transfer rate of a cluster of touching, identical spheres with the same Grashof number was found to decrease as the number of spheres increased in the cluster.

Research paper thumbnail of Effects of Rod Shapes on the Drag Force of Particles in a Shear Flow

The understanding of its shape on the movement of microparticles and nanoparticles is crucial to ... more The understanding of its shape on the movement of microparticles and nanoparticles is crucial to the development of technologies of using these particles in drug delivery systems. The effect of shape on nanoparticles used in drug delivery, in particular, is a very active area of experimental investigation. Also, the determination of the drag force on nanoparticles of different shapes is very important in designing effective nanoparticle-mediated therapies. One of the common shapes of nanoparticles is rod. In this study we present a resolved discrete particle method (RDPM), which is also called the Direct Numerical Simulation (DNS), to investigate the effect of rod shapes on the drag force in a vicious fluid as compared to other particle shapes such as a sphere and a cone. These particles are assigned the same volume and placed in contact with the bottom wall in a simple shear flow. Their drag forces are computed numerically; it is found that the particle shape has a significant effect on the drag forces. In the case of a spherical particle, our results agree very well with the analytical results found in the literature. The drag force on a rod at different orientations and the motion of two rod-shaped particles of identical volume are in a shear flow are also examined. The motion of a rod-shaped particle and a cone-shaped particle in a shear flow at low Reynolds number is also compared.

Research paper thumbnail of Mixed convective heat transfer from a heated sphere at an arbitrary incident flow angle in laminar flows

The mixed convection from a heated sphere for an arbitrary flow incident angle (h) at low to mode... more The mixed convection from a heated sphere for an arbitrary flow incident angle (h) at low to moderate Reynolds numbers (1 6 Re 6 100) and Richardson numbers (0 6 Ri 6 5) is studied by an immersed boundary method, thereby investigating the influence of different flow incident angles (0 6 h 6 180 ) on the buoyancy flow and heat transfer. The numerical method is validated by comparing the results with the simulation results of pure forced convection as well as those of mixed convection with assisting flow (0°flow incident angle) published in the literature. Extensive simulations for a wide range of different incident flow angles have been performed. New correlations are obtained for the overall Nusselt number (Nu) in terms of h, Ri, and Re, showing a quadratic decrease in Nu with respect to h only for 0 6 h 6 90 (aiding and cross flow) and a half bell-shaped decrease in Nu for 90 < h 6 180 (opposed flow). The combined treatment of mixed convection for the completely upward flow, cross flow, and completely downward flow (i.e. at incident angle 0°, 90°and 180°, respectively) was achieved showing almost linear relationships between the heat transfer rates and Ri for Ri P 1.

Research paper thumbnail of Direct numerical simulation of heat and mass transfer of spheres in a fluidized bed

We have developed a direct numerical simulation approach combined with the immersed boundary (DNS... more We have developed a direct numerical simulation approach combined with the immersed boundary (DNS-IB) method for studying heat transfer in particulate flows. In this method, fluid velocity and temperature fields are obtained by solving the modified momentum and heat transfer equations, which are due to the presence of heated particles in the fluid; particles are tracked individually and their velocities and positions are solved based on the equations of linear and angular motions; particle temperature is assumed to be constant. The momentum and heat exchanges between a particle and the surrounding fluid at its surface are resolved using the immersed boundary method with the direct forcing scheme. The DNS-IB method has been used to study the heat transfer of 225 heated spheres in a fluidized bed. By exploring the rich data generated from the DNS-IB simulations, we are able to obtain statistically averaged fluid and particle velocities as well as the overall heat transfer rate in the fluidized bed. Good agreement between the current study and the one by is found for the hydrodynamic properties of the bed such as pressure gradients within the bed and the relationship between fluidization velocity and bed solid fraction. The particle-averaged Nusselt number is found to increase as the fluidization velocity increases and the bed height rises; particles at the entrance of the bed tend to have the maximum heat transfer rate because of the higher particle-fluid temperature gradients in this region; as the fluid moves upward in the bed, it gets warmer, which reduces particle-fluid temperature gradients and decreases the transfer rate of particles.