2018-07-22T03:26:01Z
http://ijstm.shirazu.ac.ir/?_action=export&rf=summon&issue=261
Iranian Journal of Science and Technology Transactions of Mechanical Engineering
2228-6187
2228-6187
2005
29
6
Comparison of interface capturing methods in two phase flow
In two phase flow investigation, there is a need for robust methods capable of predicting interfaces, in addition to treating the traditional governing equations of fluid mechanics (Navier-Stokes Eqs.). Such methods in a finite volume approach can be classified into two typical categories called interface tracking and interface capturing methods. According to their abilities, interface capturing methods are of more interest in free surface modeling, especially when complex interface topologies such as wave breaking are included. These methods solve a scalar transport equation in order to find the distribution of two phases all over the computational domain. That is, all properties of the effective fluid will be calculated.
In this paper, some existing schemes will be reviewed and two high order composite schemes will be applied on a discretised form of the volume fraction convection equation. A discussion on the performance of methods will be presented as a result of different scalar distribution convection in various velocity fields according to the program that has been developed in this manner. It will be presented to show that CICSAM (Compressive Interface Capturing Scheme for Arbitrary Mesh) can be used as a good choice for free surface simulation in practice.
Interface modeling
two phase flow
volume methods
high resolution schemes
2005
12
16
539
548
Iranian Journal of Science and Technology Transactions of Mechanical Engineering
2228-6187
2228-6187
2005
29
6
Effect of hall’s current for stokes’ problem for a third grade fluid in the case of suction
Unsteady incompressible unidirectional third-grade fluid past an infinite porous wall is considered in the presence of Hall current. The plate at the lower boundary y=0 is executing sinusoidal oscillations in its own plane with superimposed blowing or suction. The governing equation (representing the velocity field) is modeled and described by a third order non-linear partial differential equation.
Non-Newtonian fluid
oscillating and accelerating boundary
blowing/suction
perturbation technique
Hall effects
2005
12
16
549
558
http://ijstm.shirazu.ac.ir/article_962_a3fac17f1736ce4b71b74ff41ba1c095.pdf
Iranian Journal of Science and Technology Transactions of Mechanical Engineering
2228-6187
2228-6187
2005
29
6
The use of fuzzy logic theory for selecting appropriate tool steels with price analysis
Selection of tool steels is not limited to one type of steel for satisfying customer needs. On the other hand, technical specifications of tool steels are not absolute and it consistently deviates from the mean. Thus in this paper, the fuzzy logic theory has been used for selecting appropriate tool steels with price analysis. The main steps are as follows:
Tool steels selection
Fuzzy Logic
customer’s needs
price analysis
2005
12
16
559
567
http://ijstm.shirazu.ac.ir/article_963_2c5a3f5e3dcc5fb9c2ba21f28b503537.pdf
Iranian Journal of Science and Technology Transactions of Mechanical Engineering
2228-6187
2228-6187
2005
29
6
Finite element model updating of rotating structures using different optimisation techniques
This paper is concerned with finite element model updating of rotating structures using measured vibration test data. The use of both deterministic and stochastic optimisation techniques was investigated in order to minimise the difference between the measured and analytical data. First, a theoretical basis was developed for frequency response functions (FRFs) updating techniques. The standard linear least-square (LLS) formulation was applied to the FRF updating formulation where the element mass, damping, gyroscopic and stiffness matrices are corrected by using a single multiplier, the so-called p-value. A new residue was then proposed and formulated to improve the convergence rate of the FRF-based model updating in the presence of noise. Next, two well-known stochastic optimisation methods that require no gradient and can achieve a global optimal solution in solving non-smooth and highly non-linear optimisation problems, namely genetic algorithm (GA) and adaptive simulated annealing (ASA), were introduced and implemented to the developed rotating structure code. The findings were illustrated in the case of a test rotor and the advantages and disadvantages of the proposed techniques were discussed in some detail.
Model updating
modal analysis
optimization techniques
2005
12
16
569
585
http://ijstm.shirazu.ac.ir/article_964_d3ed641be6776f66637a9efe27c2fdbb.pdf
Iranian Journal of Science and Technology Transactions of Mechanical Engineering
2228-6187
2228-6187
2005
29
6
Characterizing gravity recoverable pgms and gold in grinding circuit
At McGill University, Canada, a successful Knelson technology for gravity recoverable gold (GRG) has been used to process more than 200 representative gold ore samples all over the world since the early 1990s. In recent years, the applications of this technology have expanded to platinum group metals (PGM). The investigation of INCO Clarabelle Mill grinding circuit products shows that, like gold, PGM selectively enrich in some of the grinding products, such as ball mill discharge and cyclone underflow, and they are amenable to gravity separation. The gravity recoverable PGMs and Au were well characterized with a combination of regular Knelson and Variable Speed Knelson technology.
Knelson concentrator
centrifugal separation
platinum group metals
Gold
2005
12
16
587
596
http://ijstm.shirazu.ac.ir/article_965_697fb4e7a75f673ef65356b55d77b1c9.pdf
Iranian Journal of Science and Technology Transactions of Mechanical Engineering
2228-6187
2228-6187
2005
29
6
Developing an experimental model to estimate the dispersion number for a pilot flotation column in sarcheshmeh copper complex
Two empirical models are presented in order to determine the dispersion number and mean residence time for the pilot scale column cell in the Sarcheshmeh copper complex. To check the accuracy of these models a series of continuous flotation tests were also performed. Mixing condition and residence time distribution were also evaluated in the column. Continuous kinetic tests and examination of the model accuracy were also performed at three different residence times. Empirical equations developed for the prediction of the dispersion number cannot be generalized to every situation, but using this model one can develop an empirical relationship to be applied for the pilot scale column in Sarcheshmeh, the result of which is in good correlation with those obtained from RTD tests. By comparing the recovery from a mixing condition and that obtained from continuous kinetic tests, the accuracy of the empirical equation was shown.
Column flotation
dispersion number
residence time
Sarcheshmeh copper complex
2005
12
16
597
601
http://ijstm.shirazu.ac.ir/article_966_e06a45da5eb08a6a07996aad93c5220a.pdf