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This paper aims to investigate the behavior of a spherical absorber composed of two parts, an inner sphere and a supporting convex spherical dish in which the ball is placed. Considering only the planar behavior of the system, a set of governing nonlinear differential equations was derived and solved numerically. Firstly, the system is exposed to the harmonic excitation of the supporting bowl and its time response is analyzed for all time dependent variables. By gradually changing the angular frequency of the excitation, a resonance curve is obtained, which is examined in detail with respect to the changing amplitudes of the excitation force and the nonlinear behavior. The effect of internal damping and different settings of the absorber characteristics are also investigated. The effect of initial conditions without the presence of an external excitation force is also numerically analyzed by means of phase portraits for selected pairs of initial conditions. [ABSTRACT FROM AUTHOR]

A novel technique to accelerate optimization-driven aerodynamic shape design is presented in the paper. The methodology of optimization-driven design is based on the automated evaluation of many similar shapes which are generated according to the output of an optimization algorithm. The vast amount of numerical simulations makes this process slow but the resource-intensive simulation part can be changed to so-called surrogate models or metamodels. However, there isn't any guarantee of this solution's accuracy. The motivation of this work was to develop an acceleration method to speedup optimization sessions without losing accuracy. Accordingly, the numerical simulation is kept in the pipeline but it is initialized with a velocity field that is close to the expected solution. This velocity field is generated by a predictive initializer that is based on a convolutional deep neural network. The network has to be trained before using it for initializing numerical simulations; the data generation, the training and the testing of the network are described in the paper as well. The performance of predictive initializing is presented through a test problem based on a deformable u-bend geometry. It has been found that the speedup in the convergence speed of the numerical simulation depends on the resolution of the predictive initializer and on the handling of velocities in the near-wall cells. A speedup of 13% was achieved on a test set of 500 geometries that were not seen by the initializer before. [ABSTRACT FROM AUTHOR]

This paper aims to increase the effectiveness of the Maximum Power Control (MPC) strategy by using a new Adaptive Maximum Power Control method (AMPC) for maximizing the power delivered by the Wind Turbine System (WTS) during partial load operation whatever the disturbances caused by variations in wind profile. The AMPC is applied to one of the frequently used Maximum Power Point Tracking (MPPT) methods called as Optimum Torque (OT) MPPT algorithm. Furthermore, the proposed AMPC strategy aims to optimize the wind energy captured by the WTS during partial load operation under rating wind speed, using Fuzzy-Logic as Adaption Mechanisms (AMPC- FLC). Additionally, the performances of the proposed improved OT-MPPT method based on AMPC-FLC are compared to the OT-MPPT method based on Conventional Maximum Power Control (CMPC-PI) under the same conditions. The robustness, dynamic performance, and fast approximation of the optimal value are proved with the numerical simulations under MATLAB/Simulink® software. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to present an inventory balance model including an order-up-to replenishment policy with partial backlogging. Pictured in the model is a situation, where goods are not replenished continuously, but only at predetermined intervals. The model is described by ordinary differential equations with delayed argument because of the assumption of a time lag between ordering and delivery. A computer simulation which helps to demonstrate and verify model behaviour is utilized for the numerical solution of the model. Sales data of a real company are used as the input data. Due to the comparison of the designed model outputs against the real state in the company, it was verified that it is possible to achieve a substantial reduction in warehousing costs without a disproportionate increase in the risk of inventory shortage. The authors note that modern methods of functional analysis can be successfully applied in solving an inventory balance model. [ABSTRACT FROM AUTHOR]

The paper introduces a hardware-in-the-loop (HIL) vehicle simulator built for testing and tuning a look-ahead cruise control algorithm considering forward road conditions. The aim of the vehicle simulator, apart from conducting real-time demonstrations and tests, is to create a HIL architecture which can be directly applied to a real heavy-duty vehicle formerly represented in TruckSim. By this means, several otherwise expensive road tests can be implemented with the simulator to increase the efficiency and reliability of the developed lookahead control method. [ABSTRACT FROM AUTHOR]

This paper involves the design and construction of the intake manifold system of the FSAE car including the air shroud, air filter, throttle body, restrictor plenum, fuel injectors, fuel rail and runners. To ensure the quality, the proposed system is designed based on the FSAE rules. The design process of the intake manifold system will consist of the usual engineering processes including computer modelling, Finite Element Analysis and finally Computational Fluid Dynamics testing in order to determine the validity of the model and to tune the design in order to obtain the optimum performance out of the intake manifold system as a whole. [ABSTRACT FROM AUTHOR]

On the example of the road pavement of a semi-rigid structure, this paper presents the concept of the parameters estimation of the experimental section tested after 30 years of use. In the context of the lack of technical history data of the analyzed road section, the resultant (conventional multilayer system, which is pavement and its subgrade) stiffness was analyzed in relation to the moment it was built. The analysis was performed using the concept of multilevel loadings, with the use of FWD-type equipment. The considerations are related to the slope coefficients of linear regression obtained on the basis of a research program in the range of the loads up to 90 kN. There were compared the differences between slope of the regression function for the force-deflection relation between the results of the deflection measurements of the test section after 30 years of use and the slope coefficients for the pavement structure parameters estimated on the basis of both expert judgments and computer simulations, as well as the back forecast. For the forecast, the properties of the stochastic process determined by the Poisson distribution were used. [ABSTRACT FROM AUTHOR]

Several different seismic active control algorithms have been proposed in the last decades, most of these studies are based on the applications of the traditional linear quadratic regulator control (LQR). This paper develops a new control algorithm for SDOF structures based in Lyapunov method. This algorithm uses Lyapunov's direct approach for stability analysis in design of feedback controller. The approach requires the use of Lyapunov function candidate, which must be a positive definite function of the states of the system. The controller is designed so as to make the derivative of the Lyapunov function negative semidefinite. Numerical simulations using one story frame structure modeled as shear building structure subjected to earthquake excitations have been performed to evaluate the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

In this paper, the authors developed a three dimensional shell-spring numerical model of a shield tunnel, in which the elastic shell elements were adopted to model the segments and the spring models were used for the simulation of the segmental joints. The highlight of this research is that the non-linearity of the joint bending stiffness was taken into consideration, which was first determined through the numerical simulation by using a refined 3D continuum model of the segment-joint structure. The automatic iteration of the joint bending stiffness was achieved through programming with the ANSYS ADPL software. Based on a specific engineering example, a 3D continuum-shell-spring model was established to analyze the internal forces of shield tunnel segmental linings subject to swelling soils. The developed numerical model and its application in the analysis of the internal forces of shield tunnel segmental linings in swelling ground will provide useful reference and guidance for the numerical calculation in similar engineering projects in future. [ABSTRACT FROM AUTHOR]

Sea ice crashing against offshore structures can cause strong ice-induced vibration and have a major impact on offshore structural safety and serviceability. This paper describes a numerical method for the prediction of ice-induced vibration when a vertical offshore structure is subjected to the impact of sea ice. In this approach, negative damping theory and fracture length theory are combined and, along with ice strength-stress rate curve and ice failure length, are coupled to model the internal fluctuating nature of ice load. Considering the elastic deformation of ice and the effect of non-simultaneous crushing failure of local contact between ice and structures, the present ice-induced vibration model is established, and the general features of the interaction process are captured. To verify its efficacy, the presented simulation methodology is subjected to a model test and two full-scale measurements based on referenced studies. Example calculations show good agreement with the results of the model test and full-scale measurements, which directly indicates the validity of the proposed simulation method. In addition, the numerical simulation method can be used in connection with FE programs to perform ice-induced vibration analysis of offshore structures. [ABSTRACT FROM AUTHOR]

Transpired solar collector (TSC) systems are simple solutions for the preheating of ventilation air with solar energy. Their performance is a function of several environmental factors, so the climatic conditions of the location play an important role. In this paper, the effect of different climatic zones on the thermal performance of the TSC is investigated. To exclude other sources of influence, the same reference industrial building is examined in four Turkish locations (Antalya, Istanbul, Ankara and Sivas) representing different climatic conditions. RETScreen simulation is carried out for all four regions to obtain the drop of conventional heating requirement in case absorber azimuth of 0°, 45° and 90°. To illustrate the performance, temperature rise, heating energy savings and annual solar fraction are presented. Generally, it can be stated that a location with cold climate and high solar radiation at the same time benefits most from the use of a TSC system. A mathematical correlation has been found showing the solar fraction's dependence on solar radiation and heating degree days. Finally, simulation results have been compared to a set of measurement data from an industrial building's TSC system near Istanbul. [ABSTRACT FROM AUTHOR]

Results are given for the comparative numerical simulation of heat-and-mass transfer processes in the cooling passages of a cylinder head in diesel locomotive engine 16 FN 26/27 running under rated power conditions at different engine boost levels. The advanced numerical methods used are shown to ensure a high degree of accuracy and information content when simulating heat-and-mass transfer processes, and enable evaluating the local values of flow parameters with account of the complex configuration of the flow parts in the cooling passages and the impact of operating parameters. The results show that an increasing boost level of a diesel engine and, respectively, a growing thermal load degrade drastically the conditions of heat rejection from the most thermally stressed zones of the cylinder head - the central part of the bottom face in the area of the injector bore and of the bridge between the bores of exhaust valve seats. The paper assesses the impact of the boost level on the effectiveness of heat rejection from the most thermally stressed areas of the cylinder head of a diesel locomotive engine. Conclusions and recommendations for improving the operating conditions of the cylinder head are given. [ABSTRACT FROM AUTHOR]

Dynamic Positron Emission Tomography (PET) reconstructs the space-time concentration function of a radiotracer by observing the detector hits of gamma-photon pairs born during the radiotracer decay. The computation is based on the maximum likelihood principle, i.e. we look for the space-time function that maximizes the probability of the actual measurements. The number of finite elements representing the spatio-temporal concentration and the number of events detected by the tomograph may be higher than a billion, thus the reconstruction requires supercomputer performance. The enormous computational burden can be handled by graphics processors (GPU) if the algorithm is decomposed to parallel, independent threads, and the storage requirements are kept under control. This paper proposes a scalable dynamic reconstruction system where the algorithm is decomposed to phases where each phase is efficiently mapped onto the massively parallel architecture of the GPU. [ABSTRACT FROM AUTHOR]

Building collapse in earthquakes caused huge losses, both in human and economic terms. To assess the risk posed by using the composite members, this paper investigates seismic failure probability and vulnerability assessment of steel-concrete composite structures constituted by rectangular concrete filled steel tube (RCFT) columns and steel beams. To enable numerical simulation of RCFT-structure, the details of components modeling are developed using OpenSEES finite element analysis package and the validation of proposed procedure is investigated through comparisons with available experimental results. The seismic fragility and vulnerability curves of RCFT-structures are created through nonlinear dynamic analysis using an appropriate suite of ground motions for seismic loss assessment. These curves developed for three-, six- and nine-story prototypes of RCFT-structure. Fragility curves are an appropriate tool for representing the seismic failure probabilities and vulnerability curves demonstrate a probability of exceeding loss to a measure of ground motion intensity. [ABSTRACT FROM AUTHOR]

Vortex shedding flowmeters can be used for a wide range of flow measurement applications with various kinds of fluids. The critical point in applying this method comes from the assumption that the Strouhal number is constant for the given Reynolds number range. In some cases - typically regarding flowmeters with narrow gauge pipes -, this assumption is only partially met, thus limiting the widespread use of these instruments in certain industrial appliances. The paper presents a diagnostic investigation on the effects of this nonconstant behavior. The method elaborated in this report can be applied to vortex flowmeters with narrow gauge pipes. In these instruments - usually due to the narrow cross-sections of the gauge pipe - measurement possibilities are limited, thus it is not possible for the user to determine the effects of the nonconstant behavior. To conduct these investigations, a calibration rig was designed and assembled. The presented diagnostic method combines measurements and numerical simulations. The results of the investigations can be used in the data processing phase, in order to reduce the uncertainty of the volume flow rate measured by vortex flowmeters. [ABSTRACT FROM AUTHOR]

The Tunnel Boring Machine (TBM) tunneling process in hard rock is actually breakage of a rock mass that is not necessarily intact. Thus, undoubtedly, joints and discontinuities play a role in TBM performance. In addition, this performance depends on the rock breakage efficiency induced by the TBM cutterhead. Both the rock mass and the TBM specifications affect the rock breakage and chipping process and thus in the machine efficiency. In this paper, the chipping process in a type of jointed hard rock under indentation by two TBM disc cutters has been numerically simulated using the Discrete Element Method (DEM) in two dimensions. The spacing of the cutters has been optimized regarding optimization of some defined criteria such as chip thickness, chipping area and also significantly the penetration rate. The optimum cutter spacings on the selected hard and jointed rock were identified to be in the range about 110 to 140 mm for different joints frequencies. According to the simulation results, it is believed that the numerical simulation will contribute to an improved knowledge of rock fragmentation, which will in turn help to enhance mining, drilling and tunneling efficiency through the improved design of mining tools and equipment. [ABSTRACT FROM AUTHOR]

Numerical simulations make the improvement of fabrication process and welding technology. Numerical simulations make the improvement of fabrication process and welding technology possible. Using finite element method the most important information about welded specimens can be determined such as deformed shape, residual stresses or even microstructural properties like phase proportions or hardness. The current study focuses on the modelling background of welding processes and the effects of different welding parameters on residual stresses and deformations. The paper focuses on heat sources, temperature dependent material properties and the development of a thermo-mechanical analysis. The virtually fabricated specimens are further analysed to investigate the stability behaviour. [ABSTRACT FROM AUTHOR]

In this paper, the effect of rock bridge surface on the shear behavior of planar non-persistent joints under low and high normal loads has been investigated using particle flow code in 2 Dimensions. PFC2d was calibrated with respect to the data obtained from experimental laboratory tests to ensure the conformity of the simulated numerical models response. The models consisting non-persistent joint were simulated and tested by shear loading under low and high normal loads. The discrete element simulations demonstrated that the failure pattern was mostly influenced by normal load, while the shear strength was linked to the failure pattern and failure mechanism. The failure patterns were found reasonably similar to the experimentally observed trends. [ABSTRACT FROM AUTHOR]

Modern engine exhaust restriction valves can be applied not only as retarders. A suitable pressure generation can assist the aftertreatment system (exhaust gas temperature management) and raw emission control as well. To provide these functionalities the exhaust backpressure has to be controlled arbitrarily. In this paper a model-based controller design is demonstrated to minimize calibration effort. A first engineering principle based, mean-value, nonlinear model was described and converted into linear parameter-varying (LPV) form. To satisfy the demands of the above applications the controller needs to be a high dynamic, stabilizing, tracking controller which is robust in the whole relevant engine operation range. The exhaust processes of the individual cylinders generate comparable amplitude pressure oscillations to the expected control accuracy. To fulfill the above requirements and manage the challenge of the exhaust pressure waves an H-infinity controller design method was chosen. In order to handle the saturation of the control signal a high gain anti-windup was applied. Seeking for the lowest possible computational demand the controller order reduction was proposed based on Hankel singular values. Finally the controller performance was demonstrated and evaluated in software-in-the-loop simulations. [ABSTRACT FROM AUTHOR]

Semi-circle bending (SCB) test is an important test in the field of rock fracture. In order to investigate the propagation process of 3-D internal cracks under semi-circular bending, numerical simulations of SCB specimens were carried out based on the finite element method and adaptive mesh technique. The results show that the numerical simulation results of this method are in good agreement with the previous laboratory test. The symmetrical loading model belongs to the pure I loading where the value of KI is positively related to the bottom load span S/R. The asymmetric loading model belongs to mix-mode loading. With the increase of unilateral load span S2/R, there is a decline and then a rise of the value of SIF at the same point at the crack tip. The S2/R is an important factor affecting the mechanical properties of rock specimens. The crack propagation path was obtained based on the maximum tensile stress (MTS) criterion. In-plane propagation of the internal crack in the symmetrically loading model leads to failure of the specimen. Wing propagation of the internal crack in the asymmetrically loading model causes the specimen to fracture into two asymmetrical parts. Quantitative analysis of the internal crack propagation of the symmetrical loading model shows that the growth rate of the lower end of the crack is the largest, and the upper end of the crack is the smallest. The above results can provide a reference for the research on the propagation of 3-D internal cracks of SCB specimens. [ABSTRACT FROM AUTHOR]

Forming of blanks during stamping by rolling (RS) is possible according to technological schemes of deposition, landing, direct and reverse extrusion, distribution and compression, etc. Controlling the relative position and shape of the deformed tool allows you to control the direction of flow of the workpiece material and the nature of its formation, as well as the stress-strain state of the material. The complexity and versatility of RS processes necessitate computer modeling for sound management of basic technological parameters. Physical experimental as well as computer modeling of the RS process in the DEFORM-3D software package was performed in the work. According to the results of computer simulation, the distribution of deformation components, stresses and temperatures in the deformed workpiece area was obtained, and using the Cockroft-Latham criterion, the destruction of metals during cold deformation was also predicted. Physical modeling of the SR process on lead blanks confirmed the nature of their deformation, obtained by computer simulation. And the analysis of the stress-strain state of the material based on the results of measurements of the deformed grid confirmed the validity of the appointment of boundary conditions in computer simulation. This approach is suitable for modeling by the method of SR of any metal models, for which it is necessary to know their mechanical characteristics, including boundary deformation curves. [ABSTRACT FROM AUTHOR]

The study is motivated by the industrial problem from pharmaceutical industry, which is ethanol and methanol removal from process wastewater. To complete this goal hybrid method is investigated and optimized. Two distillation columns are sufficient for separation of alcohol-water mixture. Suitable water can be purified as bottom product of first column. Ethanol and methanol purification is achieved with combination of second distillation column and pervaporation. The target of this research is to rigorously model and optimize the separation of water-ethanol-methanol ternary mixture in professional flowsheet simulator environment. The minimal sufficient membrane transfers area and number of minimal theoretical stages of the columns are determined. Cost estimation is also investigated according to Douglas methodology. Considering the simulation and economic results it can be determined that, the hybrid configuration is suitable for separation of ternary mixture in 99.5 weight percent purity. [ABSTRACT FROM AUTHOR]

In this study, the hydraulic jumps over rough beds are numerically simulated. In order to calibrate the numerical model, the experimental data were used, which performed in a rectangular flume in various roughness arrangements and different Froude numbers. The effect of the distance (s) and the height (t) of the roughness on different characteristics of the hydraulic jump, including the sequent depth ratio, water surface profile, jump's length, roller's length, and velocity distribution were evaluated and compared. The results showed that the numerical model is fairly well able to simulate the hydraulic jump characteristics. The results also showed that the height and distance of roughness slightly reduced the sequent depth ratios for all Froude numbers. Also, the hydraulic jump length is reduced at the presence of the rough bed. Velocity profiles in different experiments were similar and there was a good agreement between simulated and measured results. Also, increasing the distance and the height of the roughness will slow down the velocity near the bed, increase the shear stress, and increase the gradient of the velocity distribution near the bed. [ABSTRACT FROM AUTHOR]

In the recent years 3D printing became a hot topic, however it’s hard to design parts without a deep understanding of the material properties. The usage of these materials in vehicles assumes the knowledge of the behavior in dynamical environment. The aim of this study is to estimate the modal parameters and the damping properties via experimental dynamic analysis of a part made from PLA. With the results we can provide data for the FEM softwares’ input. After the numerical simulations the simulated results were compared to the measured data. [ABSTRACT FROM AUTHOR]

One of the key points in numerical simulation of coal-rock cutting by conical picks is to select a proper coal-rock constitutive model. In order to find a reasonable coal-rock constitutive model, a uniaxial compression test was conducted to obtain the constitutive model. The several stages for linear elastic deformation and creep, plastic yielding, hardening, and finally brittle cracking of the constitutive units were studied, and the coal-rock constitutive model was established. As a result, the coal-rock cutting by one conical pick or two conical picks was simulated and the results were compared with coal-rock cutting experiment on a Coal-rock Cutting Machine. According to the simulation and experimental results, it is believed that the numerical simulation can reveal coal-rock crushing process. And the total error rate of coal-rock cutting by one conical pick between the simulation and experiment is 8.5%. The maximum deviation of coal-rock cutting by two conical picks between the simulation and experiment is 9.8%. All simulation values are within a reasonable range. The comparison indicates that the coal-rock constitutive model should better be defined considering the coal-rock crushing process by conical picks. [ABSTRACT FROM AUTHOR]

The goal of the article is to identify the influence of geometrical parameters of the axial inlet device, presence of its walls rotation and the pump flow rate on components of the absolute velocity distribution at the impeller inlet. A numerical simulation in the software ANSYS CFX and analysis of liquid flow structure of a double entry centrifugal pump were carried out. The axial inlet device is shaped by cylindrical and diffuser section, which includes fairing in front of the impeller. Four models of the axial inlet casing were researched. In the analyzed variants of geometry of the axial inlet device, structure of absolute velocity distribution component is similar. Rotational speed of 1450 rpm of the rotational walls of the axial inlet device compared to fixed walls affects the change of distribution of an axial component of the absolute velocity more than circumferential. Introduction of sudden expansion at the impeller inlet reduces the average value of the circumferential velocity and improves the axial velocity components distribution. Maximum and average value of the axial component of the absolute velocity and its unevenness in cross-section of the intake reduces while reducing the pump flow rate. [ABSTRACT FROM AUTHOR]

Constant rate of strain (CRS) and incremental loading (IL) consolidation tests are extensively used to measure consolidation properties of clayey soils. However, results of CRS test are usually strain rate dependent. In this study, a finite differences simulation of CRS test based on Terzaghi's theory of consolidation is performed. The numerical simulation permits to evaluate a strain rates range satisfying a preset relative pressure criterion. Results of simulation show that the required relative pressure criterion can be verified, during the steady state stage of CRS test, only for particular types of soils and particular range of strain rates. Subsequently, a simple method is proposed to select, for a soil sample defined by its initial height, initial void ratio and liquid limit, an appropriate strain rates range satisfying the ASTM 4186-06 criterion. Comparison of previsions and experimental results reported in literature shows good agreement. [ABSTRACT FROM AUTHOR]

This work presents the assessment of the mean flow field and low frequency disturbances in the stay vane channel of a model pump turbine using transient numerical simulations and LDV-based measurements. The focus is laid on transient CFD simulations of characteristic flow states in the stay vane channel when operating at off-design conditions in pump mode. Experimental and numerical investigations obtained a shifting velocity distribution between the shroud and hub of the distributor when continuously increasing the discharge in the part-load range. Simulations captured the occurrence of this changing flow state in the stay vane channel reasonably well. A further increase of the discharge showed a uniformly redistributed mean flow of both hub and shroud side. Monitoring points and integral quantities from measurements and transient simulations were used to interpret the development of transient flow patterns in the stay vane channel at the operating point of strongest asymmetrical flow. During simulation and measurement, a dominant rotating stall inception was observed near the design flow of the pump turbine. At this point where the stall becomes severe, a high level of correlation between the signals of the upper and lower stalled flow in the stay vane channel was calculated. Further simulations for different guide vane positions predicted a strong influence of the guide vane position on the structure of rotating stall. [ABSTRACT FROM AUTHOR]

The present study considers the tensile strength of concrete samples in direct, flexural, double punch and ring tests using both of the experimental tests and numerical simulation (particle flow code 2D). It determined that which one of indirect tensile strength is close to direct tensile strength. Initially calibration of PFC was undertaken with respect to the data obtained from Brazilian laboratory tests to ensure the conformity of the simulated numerical models response. Furthermore, validation of the simulated models in four introduced tests was also cross checked with the results from experimental tests. By using numerical testing, the failure process was visually observed and failure patterns were watched to be reasonable in accordance with experimental results. Discrete element simulations demonstrated that the macro fractures in models are caused by microscopic tensile breakages on large numbers of bonded discs. Tensile strength of concrete in direct test was less than other tests results. Tensile strength resulted from punch test was close to direct test results. So punch test can be a proper test for determination of tensile strength of concrete in absence of direct test. Other advantages shown by punch tests are: (1) the punch test need less sample size compared with other tests, (2) less material is need for sample preparation, (3) sample preparation is easy and (4) the use of a simple conventional compression press controlled by displacement compared with complicate device in other tests. [ABSTRACT FROM AUTHOR]

In this work we consider the numerical simulation of heat transfer by natural convection in a horizontal cylindrical cell, filled with nitrogen gas and heated by a tungsten filament situated on its axis. The gas temperature range is from 400K to the envelope of the lamp unto the 3000K near tungsten wire. These temperatures create large temperature gradients (up to 500K/mm) which produce complex patterns of currents circulating inside the cell. The physical principles governing this problem are modeled by the Navier-Stokes equations. These equations are solved numerically using the finite volume method. Numerical results show that the temperature gradients cause the generation of the thermal buoyancy force which induces a natural convection movement within the cell. The numerical results are in good agreement with those of an experimental study conducted by the Coherent Anti-Stokes Raman Scattering (CARS) technique with the same geometric, dynamic and thermal parameters. [ABSTRACT FROM AUTHOR]