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Existing fluid simulation techniques mainly process single-phase fluids, and they have difficulties in accurately simulating and visualizing multiphase fluid dynamics. This paper proposes a new method for the real-time rendering of multiphase fluid simulations, which uses smoothed particle hydrodynamics in screen space. Meanwhile, the method employs phase fraction textures to differentiate various materials in multiphase fluid simulations, thereby portraying mixing and separation effects more realistically. Besides, efficient texture computation allows it to be integrated seamlessly into real-time simulation rendering workflows. Extensive testing confirms the effectiveness of the proposed method in rendering multiphase fluid behaviors with high visual fidelity and demonstrates its capability to process frames within 0.01 s, even in cases with up to 300,000 particles. This study enhances the fluid dynamics simulation field and provides a more accurate and efficient method for visualizing complex multiphase fluids in simulations. [Display omitted] • Novel method for real-time rendering of multiphase flows, addressing miscible fluid challenges. • Achieves rapid rendering of complex fluid dynamics with high computational efficiency. • Outperforms existing methods for rendering immiscible multiphase fluids. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a dynamic model of a counter flow water to oil heat exchanger when all inputs (inlet temperatures of the fluids and the mass flow rates) are simultaneously varying. Although interesting results about modeling of heat exchanger by linear parameter varying (LPV) can be found in , several problems remain to be solved such as the structure estimation or a proper initial MISO model for the optimization algorithms. This paper introduces a new model structure called quasi LPV model which simulates accurately the temperature and flow transients in a counter flow heat exchanger (COFHX). The quasi LPV model is compared to a realistic numerical model of a counter flow heat exchanger adjusted with the test rig heat exchanger of the University of Valenciennes in France. Comparisons indicate that the developed quasi LPV model is capable of predicting the transient performance of the heat exchangers satisfactorily. [Copyright &y& Elsevier]

Abstract: This paper presents a numerical model for the simulation of a swash-plate axial piston pump, focusing on the characterization of fluid properties. As it is well known, the reduction of flow oscillations (which generates pressure ripples and produces vibration and noise in the entire circuit) and the avoidance of cavitation are the major problems in the design of these pumps. Developing a simulation code can be very useful for component optimisation in order to predict and reduce the undesired phenomena. The paper first gives a quick overview on a previously developed pump model; afterwards four different models of the fluid are presented: they take into account cavitation in different ways. Their aim at characterizing as well as possible the unsteady and erratic cavitation features in a simplified manner, in order to apply the models to the simulation of hydraulic components. In the second part of the paper an application is shown of these models to an axial piston pump: a few results are presented and compared with available test data. The effects of the fluid models on the predicted pump performance are shown and commented. [Copyright &y& Elsevier]

Highlights: [•] A model to evaluate fluid properties considering the dynamic features of cavitation is presented. [•] The new model for the evaluation of fluid properties is suitable for lumped parameters models. [•] The paper studies the operation of gear pumps under cavitating conditions. [•] Experimental activity on a gear pump was performed to validate the modelling approach. [Copyright &y& Elsevier]

Abstract: In this paper, the modeling and simulation of the gas-damped double-gimbaled electrostatic torsional micromirror are presented. The model is represented as a system of coupled equations, and combines both the distributed and lumped parameter description. It involves electrostatics, solid mechanics and gas dynamics. The bending effect of the micromirror suspensions is also considered. Based on the model, the micromirror behavior has been simulated and the simulation results are presented. The model is applicable for wide class of electrostatic MEMS actuators. Moreover, the great advantage of the presented model is enormous reduction in computational time in comparison with the model completely based on the finite element analysis. [Copyright &y& Elsevier]

Abstract: This paper presents finite element modelling of the effects of different flow velocities on the structural behaviour of a skewed integral bridge. Flow velocities affect the scour depths at the piles of a bridge and thus affect its structural behaviour. Laboratory tests on a scaled-down hydraulic model along with numerical modelling were performed to simulate the structural behaviour of the scoured integral bridge. A finite element package was used for the numerical modelling work, and the displacements and strains corresponding to the measured locations on the physical model were extracted. The experimental and numerical results for the case of maximum scour depths were compared. [Copyright &y& Elsevier]

Abstract: Understanding the flow fields at the micro-scale is key to developing methods of successfully mixing fluids for micro-scale applications. This paper investigates flow characteristics and mixing efficiency of three different geometries in micro-channels. The geometries of these channels were rectangular with a dimension of; 300μm wide, 100μm deep and 50mm long. In first channel there was no obstacle and in the second channel there were rectangular blocks of dimension 300μm long and 150μm wide are placed in the flow fields with every 300μm distance attaching along the channel wall. In the third geometry, there were 100μm wide fins with 150° angle which were placed at a distance of 500μm apart from each other attached with the wall along the 50mm channel. Fluent software of Computational Fluid Dynamics (CFD) was used to investigate the flow characteristics within these microfluidic model for three different geometries. A species 2D model was created for three geometries and simulations were run in order to investigate the mixing behaviour of two different fluid with viscosity of water (1mPas). Models were only built to investigate the effect of geometry, therefore only one fluid with similar viscosity was used in these models. Velocity vector plots were used in the CFD analysis to visualise the fluid flow path. Mass fractions of fluid were used to analyse the mixing efficiency. Two different colours for water were used to simulate the effect of two different fluids. The results showed that the mixing behaviour strongly depended on the channel geometry when other parameters such as fluid inlet velocity, viscosity and pressure of fluids were kept constant. In two geometries lateral pressure and swirling vortexes were developed which provided better mixing results. Creation of swirling vortexes increased diffusion gradients which enhanced diffusive mixing. [Copyright &y& Elsevier]

Abstract: This paper describes a numerical procedure for the prediction of the homogenizing performance of high pressure homogenizing valves used in diary plants. The method is based on a strict interaction between a complex CFD code and a simple homogenizing simulation code developed by the authors. This latter implements a mathematical model for the evaluation of droplets break-up, that needs an accurate evaluation of few significant fluid dynamic parameters in the whole fluid dynamic domain inside the valve. Due to the relevant pressure gradients within the flow and to the possibility of cavitation, particular attention has been paid in defining the fluid model, the mesh and the parameters required for CFD simulations. Notwithstanding the quite simple model of the homogenizing process, comparatively with the complexity of phenomena involved, the first results obtained are in general agreement with the experimental data available. These results point out the potential of the procedure proposed as a starting point for further implementation of more complex effects. [Copyright &y& Elsevier]

Abstract: This paper presents a novel modeling approach of coupling transient computational fluid dynamics (CFD) simulation with system identification for control system involving fluid flow and heat transfer. In order to illuminate the feasibility of this method, a fluid flow and heat transfer related process, i.e. a three dimension (3-D) spatio-temporal air temperature distribution and input (inlet air temperature) dependent process in the desert climate chamber, is considered. The distributed parameter models of the chamber temperature are identified using transient CFD simulation results and are then validated against the results obtained from the CFD simulations with high RT 2 (more than 0.97) and negative Young’s information criterion (YIC, less than −11.8). The PI controllers embedded in CFD simulation are then developed based on the models. The performance of the closed-loop systems is also evaluated within the full-scale CFD model. The results show that CFD-based system identification is feasible to model fluid flow and heat transfer related processes. [Copyright &y& Elsevier]

In this paper, we develop a simplified mathematical model (a metamodel) of a simulation model of conflict, based on ideas drawn from the analysis of more general physical systems, such as found in fluid dynamics modelling. We show that there is evidence from the analysis of historical conflicts to support the kind of emergent behaviour implied by this approach. We then apply this approach to the development of a metamodel of a particular complexity based simulation model of conflict (ISAAC), developed for the US Marine Corps.The approach we have illustrated here is very generic, and is applicable to any simulation model which has complex interactions similar to those found in fluid dynamic modelling, or in simulating the emergent behaviour of large numbers of simple systems which interact with each other locally. [Copyright &y& Elsevier]