Event-driven molecular dynamics (EDMD) is a special application of Molecular Dynamics (MD) derive... more Event-driven molecular dynamics (EDMD) is a special application of Molecular Dynamics (MD) derived from kinetic theory of gases. While classical solution of Navier-Stokes equations fails at high Knudsen (Kn) number flows, EDMD is valid on entire regime. Interaction potentials are considered discrete and exist only at the moment of impact. Hence, molecule trajectories are linear. Unlike the classical MD, this helps to simulate bigger systems. Molecular interactions, interaction times and partners can be predicted deterministically. Diatomic and polyatomic molecules are handled by an implemented energy relaxation scheme. Calculation of possible event times and determination of the earliest are the most time-consuming steps of the simulation. In order to improve computational speed, a cell partitioning methodology and a priority queue structure are implemented in this study. The effect of the implementations on the performance is investigated and optimum simulation parameters are dete...
This paper presents the application of an active energy management strategy to a hybrid system co... more This paper presents the application of an active energy management strategy to a hybrid system consisting of a proton exchange membrane fuel cell (PEMFC), battery, and supercapacitor. The purpose of energy management is to control the battery and supercapacitor states of charge (SOCs) as well as minimizing hydrogen consumption. Energy management should be applied to hybrid systems created in this way to increase efficiency and control working conditions. In this study, optimization of an existing model in the literature with different meta-heuristic methods was further examined and results similar to those in the literature were obtained. Ant lion optimizer (ALO), moth-flame optimization (MFO), dragonfly algorithm (DA), sine cosine algorithm (SCA), multi-verse optimizer (MVO), particle swarm optimization (PSO), and whale optimization algorithm (WOA) meta-heuristic algorithms were applied to control the flow of power between sources. The optimization methods were compared in terms of...
In the present study, fourth-order compact formulation has been improved for Navier-Stokes (N-S) ... more In the present study, fourth-order compact formulation has been improved for Navier-Stokes (N-S) equations, which is expressed for two-dimensional, steady, incompressible flow problems. N-S equation system has been expressed with Stream Function-Vorticity Approach using Finite Difference Method (FDM) from the numerical methods. In order to test the functionality and applicability of the improved numerical formulation, a sample for submerged bluff bodies, flow problem around cylinder with square cross-section was chosen as a benchmark problem. As a result of applying improved numerical formulation with Gauss-Seidel Relaxation Method was used for this benchmark problem. The benchmark problem was also solved with second-order accuracy and obtained numerical results were compared with fourth-order accuracy numerical results. With the same Reynolds Number and the same free-stream velocity values, fourth-order numerical results are more convergent than second-order numerical results. Furt...
In this paper, the mechanical and aerodynamic design, carbon composite production, sensor-actuato... more In this paper, the mechanical and aerodynamic design, carbon composite production, sensor-actuator integration and flight tests of a new unmanned aerial vehicle, which is capable of vertical takeoff and landing like a helicopter and long range horizontal flight like an airplane, is presented. Performance of the sensor actuator integration is verified with simulations and experiments.
Aps Division of Fluid Dynamics Meeting Abstracts, Nov 1, 1998
Molecular dynamics simulations of gases were modeled by hard sphere molecules, in order to examin... more Molecular dynamics simulations of gases were modeled by hard sphere molecules, in order to examine gas properties in the neighborhood of boundaries. All collisions, both interparticle and particle-boundary, were taken as specular. The computations were done using a parallelepiped domain. Long time average values were obtained of the spatial distributions of gas properties. It was observed that the molecular number
Classical solution of Navier-Stokes equations with nonslip boundary condition leads to inaccurate... more Classical solution of Navier-Stokes equations with nonslip boundary condition leads to inaccurate predictions of flow characteristics of rarefied gases confined in micro/nanochannels. Therefore, molecular interaction based simulations are often used to properly express velocity and temperature slips at high Knudsen numbers (Kn) seen at dilute gases or narrow channels. In this study, an event-driven molecular dynamics (EDMD) simulation is proposed to estimate properties of hard-sphere gas flows. Considering molecules as hard-spheres, trajectories of the molecules, collision partners, corresponding interaction times, and postcollision velocities are computed deterministically using discrete interaction potentials. On the other hand, boundary interactions are handled stochastically. Added to that, in order to create a pressure gradient along the channel, an implicit treatment for flow boundaries is adapted for EDMD simulations. Shear-Driven (Couette) and Pressure-Driven flows for vario...
In this study, dynamic model of an aircraft with six axes manevour capability tracking another si... more In this study, dynamic model of an aircraft with six axes manevour capability tracking another six axes moving craft is presented. In literature, simulation methods with general force and moment equations are abundant. These methods may vary from a simple basic aerodynamic model with rigid 3 degrees of freedom to complex models with elasticity effects or calculations with tensor analysis. In this study, basic assumption for the body is rigidity that excludes aeroelasticity, while other calculations are based on general forms. In the calculation of the gravitation, effects of the geodetic form of the world is included and variation of atmospheric conditions with altitude is modeled, as well. In the model, dynamics of the aircraft is defined by the update of the position and orientation by calculating the translational and rotational velocities and accelarations. For the dynamic stability in six axes, longitudunal and lateral force equlibrium states are modeled and corresponding momen...
Page 1. Dynamic Model and Control of a New Quadrotor Unmanned Aerial Vehicle with Tilt-Wing Mecha... more Page 1. Dynamic Model and Control of a New Quadrotor Unmanned Aerial Vehicle with Tilt-Wing Mechanism Kaan T. Oner, Ertugrul Cetinsoy, Mustafa Unel, Mahmut F. Aksit, Ilyas Kandemir, Kayhan Gulez Abstract— In this ...
As computational capabilities increase, molecular dynamics (MD) simulations become important tool... more As computational capabilities increase, molecular dynamics (MD) simulations become important tools of simulating reality. These simulations are especially useful for compressible gas mixture problems. In this study, binary diffusion of helium and argon was examined using a hard-sphere MD simulation method. For the sake of computational speed, low spacing ratios were chosen. Binary mass diffusion of gases in two equally
Event-driven molecular dynamics (EDMD) is a special application of Molecular Dynamics (MD) derive... more Event-driven molecular dynamics (EDMD) is a special application of Molecular Dynamics (MD) derived from kinetic theory of gases. While classical solution of Navier-Stokes equations fails at high Knudsen (Kn) number flows, EDMD is valid on entire regime. Interaction potentials are considered discrete and exist only at the moment of impact. Hence, molecule trajectories are linear. Unlike the classical MD, this helps to simulate bigger systems. Molecular interactions, interaction times and partners can be predicted deterministically. Diatomic and polyatomic molecules are handled by an implemented energy relaxation scheme. Calculation of possible event times and determination of the earliest are the most time-consuming steps of the simulation. In order to improve computational speed, a cell partitioning methodology and a priority queue structure are implemented in this study. The effect of the implementations on the performance is investigated and optimum simulation parameters are dete...
This paper presents the application of an active energy management strategy to a hybrid system co... more This paper presents the application of an active energy management strategy to a hybrid system consisting of a proton exchange membrane fuel cell (PEMFC), battery, and supercapacitor. The purpose of energy management is to control the battery and supercapacitor states of charge (SOCs) as well as minimizing hydrogen consumption. Energy management should be applied to hybrid systems created in this way to increase efficiency and control working conditions. In this study, optimization of an existing model in the literature with different meta-heuristic methods was further examined and results similar to those in the literature were obtained. Ant lion optimizer (ALO), moth-flame optimization (MFO), dragonfly algorithm (DA), sine cosine algorithm (SCA), multi-verse optimizer (MVO), particle swarm optimization (PSO), and whale optimization algorithm (WOA) meta-heuristic algorithms were applied to control the flow of power between sources. The optimization methods were compared in terms of...
In the present study, fourth-order compact formulation has been improved for Navier-Stokes (N-S) ... more In the present study, fourth-order compact formulation has been improved for Navier-Stokes (N-S) equations, which is expressed for two-dimensional, steady, incompressible flow problems. N-S equation system has been expressed with Stream Function-Vorticity Approach using Finite Difference Method (FDM) from the numerical methods. In order to test the functionality and applicability of the improved numerical formulation, a sample for submerged bluff bodies, flow problem around cylinder with square cross-section was chosen as a benchmark problem. As a result of applying improved numerical formulation with Gauss-Seidel Relaxation Method was used for this benchmark problem. The benchmark problem was also solved with second-order accuracy and obtained numerical results were compared with fourth-order accuracy numerical results. With the same Reynolds Number and the same free-stream velocity values, fourth-order numerical results are more convergent than second-order numerical results. Furt...
In this paper, the mechanical and aerodynamic design, carbon composite production, sensor-actuato... more In this paper, the mechanical and aerodynamic design, carbon composite production, sensor-actuator integration and flight tests of a new unmanned aerial vehicle, which is capable of vertical takeoff and landing like a helicopter and long range horizontal flight like an airplane, is presented. Performance of the sensor actuator integration is verified with simulations and experiments.
Aps Division of Fluid Dynamics Meeting Abstracts, Nov 1, 1998
Molecular dynamics simulations of gases were modeled by hard sphere molecules, in order to examin... more Molecular dynamics simulations of gases were modeled by hard sphere molecules, in order to examine gas properties in the neighborhood of boundaries. All collisions, both interparticle and particle-boundary, were taken as specular. The computations were done using a parallelepiped domain. Long time average values were obtained of the spatial distributions of gas properties. It was observed that the molecular number
Classical solution of Navier-Stokes equations with nonslip boundary condition leads to inaccurate... more Classical solution of Navier-Stokes equations with nonslip boundary condition leads to inaccurate predictions of flow characteristics of rarefied gases confined in micro/nanochannels. Therefore, molecular interaction based simulations are often used to properly express velocity and temperature slips at high Knudsen numbers (Kn) seen at dilute gases or narrow channels. In this study, an event-driven molecular dynamics (EDMD) simulation is proposed to estimate properties of hard-sphere gas flows. Considering molecules as hard-spheres, trajectories of the molecules, collision partners, corresponding interaction times, and postcollision velocities are computed deterministically using discrete interaction potentials. On the other hand, boundary interactions are handled stochastically. Added to that, in order to create a pressure gradient along the channel, an implicit treatment for flow boundaries is adapted for EDMD simulations. Shear-Driven (Couette) and Pressure-Driven flows for vario...
In this study, dynamic model of an aircraft with six axes manevour capability tracking another si... more In this study, dynamic model of an aircraft with six axes manevour capability tracking another six axes moving craft is presented. In literature, simulation methods with general force and moment equations are abundant. These methods may vary from a simple basic aerodynamic model with rigid 3 degrees of freedom to complex models with elasticity effects or calculations with tensor analysis. In this study, basic assumption for the body is rigidity that excludes aeroelasticity, while other calculations are based on general forms. In the calculation of the gravitation, effects of the geodetic form of the world is included and variation of atmospheric conditions with altitude is modeled, as well. In the model, dynamics of the aircraft is defined by the update of the position and orientation by calculating the translational and rotational velocities and accelarations. For the dynamic stability in six axes, longitudunal and lateral force equlibrium states are modeled and corresponding momen...
Page 1. Dynamic Model and Control of a New Quadrotor Unmanned Aerial Vehicle with Tilt-Wing Mecha... more Page 1. Dynamic Model and Control of a New Quadrotor Unmanned Aerial Vehicle with Tilt-Wing Mechanism Kaan T. Oner, Ertugrul Cetinsoy, Mustafa Unel, Mahmut F. Aksit, Ilyas Kandemir, Kayhan Gulez Abstract— In this ...
As computational capabilities increase, molecular dynamics (MD) simulations become important tool... more As computational capabilities increase, molecular dynamics (MD) simulations become important tools of simulating reality. These simulations are especially useful for compressible gas mixture problems. In this study, binary diffusion of helium and argon was examined using a hard-sphere MD simulation method. For the sake of computational speed, low spacing ratios were chosen. Binary mass diffusion of gases in two equally
Uploads