• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.3 no.2
• /
• pp.166-172
• /
• 2003

The dynamics of the DDWMR depends on the velocity difference of the two driving wheels. And which is known as a type of non-holonomic equation. By this reason, the treatment of DDWMR had become difficult and conservative. In this paper, the differential-driving wheeled mobile robot is considered. The Takaki-Surgeno fuzzy model and a control method for DDWMR is presented. The suggested controller has three control elements. The first element is fuzzy state feedback designed for eliminating the dependence of time-varying parameter. The second element is weighting controller which is designed for good frequency response. The third controller is PI-controller which is designed for good command following and robustness with un-modeled dynamics. In order for achieving the performance objective, the design of controller is based on the loop-shaping algorithm.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.1 no.3
• /
• pp.22-33
• /
• 1993

A theoretical analysis of predicting the detailed motion of a piston-crank mechanism within piston-guide clearance is presented, and the analysis is applied to the piston motion in a gasoline engine. A piston movement program is developed to calculate the piston attitude relative to the bore, the piston to bore impact velocity and kinetic energy loss and the net transverse force acting on the piston. This paper presents the formulation of a set of differential equations governing the transverse and rotational motion of a piston. These equations of motion were solved by well established Runge-Kutta method. As a result of this study, it is possible to predict the effects of piston geometry and piston pin offset on a piston motion and kinetic energy loss.

• Journal of Korean Society for Atmospheric Environment
• /
• v.23 no.6
• /
• pp.708-717
• /
• 2007

In the present study, one of the widely applied equations for gas-solid cyclones, Leith and Licht model, was evaluated based on the 3-D CFD technique. The initial and boundary values of radial position and tangential velocity obtain-ed from the CFD simulation enabled complete calculation of the nonlinear second differential equation. This approach showed about 30% errors between calculations with and without the second order differential term. The calculation by using the simple first order equation presented shorter times to migrate up to the inner wall of the cyclone than by the second order, which theoretically implies higher separation efficiency. Further comparison is now under evaluation in terms of the detailed grade efficiency.

• Proceedings of the SAREK Conference
• /
• 2008.06a
• /
• pp.603-608
• /
• 2008

A simple equation to find a optimum speed of desiccant rotor is presented in this theoretical study. Usually the determination of optimum speed of desiccant rotor requires tedious and lengthy procedures by solving governing differential equations with many complicated parameters. The determining equation of optimal rotating speed is derivated from governing differential equations with three linearization assumptions, which simplify temperature profile linear along the desiccant rotor depth, psychrometric chart within a proper range, and relative humidity-sorption capacity relation. This study shows that the dominant parameters of optimal rotating speed of desiccant rotor are NTU, flow velocity, desiccant rotor depth, and temperature different between dehumidification and regeneration. The comparison shows the good agreement between complicated calculation results and simple theoretical equation prediction.

• Nuclear Engineering and Technology
• /
• v.49 no.8
• /
• pp.1636-1644
• /
• 2017

The main purpose of this article is to describe the magnetohydrodynamic stagnation point flow of Walter-B nanofluid over a stretching sheet. The phenomena of heat and mass transfer are based on the involvement of thermal radiation and chemical reaction. Characteristics of Newtonian heating are given special attention. The Brownian motion and thermophoresis models are introduced in the temperature and concentration expressions. Appropriate variables are implemented for the transformation of partial differential frameworks into sets of ordinary differential equations. Plots for velocity, temperature, and nanoparticle concentration are displayed and analyzed for governing parameters. The skin friction coefficient and local Nusselt and Sherwood numbers are studied using numerical values. The temperature and heat transfer rate are enhanced within the frame of the thermal conjugate parameter.

• Journal of Magnetics
• /
• v.21 no.1
• /
• pp.153-158
• /
• 2016

This paper aims to discuss the Non Darcy boundary layer flow of non-conducting viscous fluid with magnetic ferroparticles over a permeable linearly stretching surface with ohmic dissipation and mixed convective heat transfer. A magnetic dipole is applied "a" distance below the surface of stretching sheet. The governing equations are modeled. Similarity transformation is used to convert the system of partial differential equations to a system of non-linear but ordinary differential equations. The ODEs are solved numerically. The effects of sundry parameters on the flow properties like velocity, pressure, skin-friction coefficient and Nusselt number are presented. It is deduced the frictional resistance of Lorentz force decreases with stronger electric field and the trend reverses for temperature. Skin friction coefficient increase with increase in ferromagnetic interaction parameter. Whereas, Nusselt number decrease.

• IEIE Transactions on Smart Processing and Computing
• /
• v.4 no.6
• /
• pp.443-449
• /
• 2015

This paper considers the physical layer security problem for a two-way vehicle-to-vehicle network, where the two source vehicles can only exchange information through an untrusted relay vehicle. The relay vehicle helps the two-way transmission but also acts as a potential eavesdropper. Each vehicle has a random velocity. By exploiting the random carrier frequency offsets (CFOs) caused by random motions, a secure double-differential two-way relay scheme is proposed. While achieving successful two-way transmission for the source vehicles, the proposed scheme guarantees a high decoding error floor at the untrusted relay vehicle. Average symbol error rate (SER) performance for the source vehicles and the untrusted relay vehicle is analyzed. Simulation results are provided to verify the proposed scheme.

• The KSFM Journal of Fluid Machinery
• /
• v.9 no.4 s.37
• /
• pp.43-48
• /
• 2006

In this study, the effect of flow settling means on the performance of fan tester were numerically investigated by using a computational fluid dynamics(CFD). The airflow rate was calculated from the pressure differential across a flow nozzle in the measuring plane and the flow settling means were generally installed in the chamber of the fan tester to provide proper airflow patterns ahead of the measuring plane. The predicted nozzle differential pressures with uniform inlet velocities were compared with the values of the ANSI/AMCA 210-99 to verify the performance of the commercial CFD code CFX 5.6. The influence of flow settling means on the measurement of airflow rate in a fan tester were discussed with various porosities and inlet jet velocities. The results obtained show that the proper band of porosities exist to meet the AMCA standard in a specified inlet jet velocity.

• Kyungpook Mathematical Journal
• /
• v.60 no.4
• /
• pp.853-867
• /
• 2020

The aim of this study was to analyze the momentum and heat transfer of a rotating nanofluid with conducting spherical dust particles. The fluid flows over a stretching surface under the influence of an external magnetic field. By applying similarity transformations, the governing partial differential equations were trans-formed into nonlinear coupled ordinary differential equations. These equations were solved with the built-in function bvp4c in MATLAB. Moreover, the effects of the rotation parameter ω, magnetic field parameter M, mass concentration of the dust particles α, and volume fraction of the nano particles 𝜙, on the velocity and temperature profiles of the fluid and dust particles were considered. The results agree well with those in published papers. According to the result the hikes in the rotation parameter ω decrease the local Nusselt number, and the increasing volume fraction of the nano particles 𝜙 increases the local Nusselt number. Moreover the friction factor along the x and y axes increases with increasing volume fraction of the nano particles 𝜙.

• Steel and Composite Structures
• /
• v.41 no.6
• /
• pp.821-829
• /
• 2021

Nonlinear dynamic response of a sandwich beam considering porous core and nano-composite face sheet on nonlinear viscoelastic foundation with temperature-variable material properties is investigated in this research. The Hamilton's principle and beam theory are used to drive the equations of motion. The nonlinear differential equations of sandwich beam respect to time are obtained to solve nonlinear differential equations by Homotopy perturbation method (HPM). The effects of various parameters such as linear and nonlinear damping coefficient, linear and nonlinear spring constant, shear constant of Pasternak type for elastic foundation, temperature variation, volume fraction of carbon nanotube, porosity distribution and porosity coefficient on nonlinear dynamic response of sandwich beam are presented. The results of this paper could be used to analysis of dynamic modeling for a flexible structure in many industries such as automobiles, Shipbuilding, aircrafts and spacecraft with solar easured at current time step and the velocity and displacement were estimated through linear integration.