Paper Title, Authors, Abstract (Issue 1, Volume 3, 2009)

Pages

Comparison of a Pressure Correction based Solver VoF Method in Moving Floor Container
Ronak Ghandriz, B. Mohsen Goudarzi

Abstract: In this paper, free surface flow problems in a 2-D container with a moving floor solved by VoF method. This numerical method (VoF) is used to employ impacted factors on dimensional analysis in laminar and turbulence cases. Comparing laminar and turbulence cases (free surface flows), in laminar flows steady state happened sooner and more symmetric circulation is formed. Then, in turbulence cases both states (with and without surface tension) have been considered and inconsiderable effect of surface tension will be presented. Also, VoF method is utilized in laminar flows (free surface) to study about some impacted factors on dimensional analysis such as different velocity for moving floor, different height of fluid in the container, different fluid properties (density and viscosity), etc. So, in free surface flows, Reynolds number has no magnitude in comparison with flows without free surface and fluid properties should be considered in advance.
 

Simulation of Evacuation Processes of Pollutants in the Room Using the Similarity Theory
Marius-Constantin Popescu, Nikos E. Mastorakis, Liliana Popescu

Abstract: Tests on models can provide both information on the verification of calculation methods and solutions that theory currently can not provide. Climate processes occurring in a site are complex and not fully capture the phenomenon of mass transfer of fluid motion and heat. Those basic methods are used hydraulic moulding, which bypass the practical difficulties created by the incompatibility of the conditions of similarity (using areas of forging, hydraulic or geometric distortion).
 

    Paper Title, Authors, Abstract (Issue 2, Volume 3, 2009)

Pages

Parameter Identification of a Two Degrees of Freedom Mechanical System
Domenico Guida, Fabio Nilvetti, Carmine Maria Pappalardo

Abstract: A method for identifying parameters of a linear mechanical system is proposed. The method is based on ERA/OKID identification method developed by Juang [1]. This procedure has been tested on a light-damped mechanical linear apparatus.
 

Dry Friction Influence on Cart Pendulum Dynamics
Domenico Guida, Fabio Nilvetti, Carmine Maria Pappalardo

Abstract: Friction influence on the control law of a inverted pendulum is analyzed. Assuming a dry friction characteristic as function described by four parameters an analysis for evaluating the friction influence on the control law is proposed. Results are proposed in figures and plots.
 

    Paper Title, Authors, Abstract (Issue 3, Volume 3, 2009)

Pages

Studies of Vortex Induced Vibration on the NACA0015
Amir H. Daei-Sorkhabi, Mohammad Zehsaz

Abstract: In this paper, numerical and experimental schemes have been developed for the response of Vortex Induced Vibration (VIV) on the thin symmetric airfoil. VIV occurs where a bluff body interacts with a fluid flow. This phenomenon can be seen in many practical or industrial applications such as heat exchanger tube bundles, marine structures, power transmission lines and airfoils. Due to VIV, the structures could be subjected to very large transverse vibrations which may lead to fatigue failure. Both of methods that used in this research have been applied on the NACA0015 with various models, such as different stiffness, flow velocity and angle of attack. A numerical method, that using finite element based software ANSYS, modal and harmonic (3D) finite element analysis have been developed, is presented to study the VIV. Also experimental method is based on the image processing and direct measurement. The results show that, in VIV the response amplitude depends upon the initial condition. Also there is a frequency with large amplitude which is smaller than the shedding frequency. Therefore in transverse VIV, resonance of the frequency occurs with the 4 th sub harmonic of vortex shedding. This is an important issue in studying resonance.
 

Instability Induced by Dry Friction
Domenico Guida, Fabio Nilvetti, Carmine Maria Pappalardo

Abstract: A theoretical analysis of the dynamic behavior of mechanical systems characterized by coupled e-lements subjected to friction force from the sliding surface is proposed. With reference to systems with one degree of freedom, and approximating the friction force as a piecewise linear function, i.e. straight line segments with a suitable slope, the positioning errors in the stop phase are studied. Dimensionless analytical relations used to predict the size of positioning errors and dimensionless diagrams are provided. Furthermore the influence of the dry friction on the dynamics of a system with two degrees of freedom is proposed. The model system consists of a body of mass m1, constrained by means of a spring and a damper to a driving support, moving relatively to its counterpart of mass m2. In the conditions stability of the position of equilibrium vibrations due the static friction and the support’s velocity have been pointed out.
 

    Paper Title, Authors, Abstract (Issue 4, Volume 3, 2009)

Pages

Numerical Simulation of Complex Flow field in Quenching Furnace with Mixture of Nitrogen-Spray Water Eject Quenching under Normal Pressure and High Velocity
Baodong Shao, Heming Cheng, Jianyun Li, Ziliang Li, Lijun Hou, Jie Hou, Lifeng Wang

Abstract: The flow field in quenching furnace designed by us is complex, and the fluid flow in furnace is the mixture of Nitrogen and spray water under normal pressure and high velocity. The two-phase flow based on mixture model is simulated by CFD software FLUENT. The velocity and pressure (static and dynamic) fields in furnace at different case (such as different inlet velocity, different volume percent of water droplet and different velocity differences between Nitrogen and spray water) are given. The less is the volume percent of water droplet, the more is the maximum velocity at outlet. The simulation results show that the flow field in furnace is complex as analysis. The results also show that the value of slip velocity between two phases has more contribution to the mixture velocity of the two-phase, and the furnace designed can accelerate the velocity of flow field.
 

Controller Choice for Car Active Suspension
Ales Kruczek, Antonin Stribrsky, Jaroslav Honcu, Martin Hlinovsky

Abstract: Automotive suspension system design is very important part of the passengers comfort and safety. In this article automotive active suspension with electric linear motor as an actuator is designed. Due to many reasons H-infinity control is used. This paper is focused on comparison of different controller designed for quart, half or full-car controller (and always used for ―full? car). Each controller configuration is simulated and then verified on the hydraulic quarter car test bed.