Investigation of the Configuration of Small Hydropower using a Novel Smoothed Particle Hydrodynamics Method

A novel Computational Fluid Dynamics (CFD) method utilizing Smoothed Particle Hydrodynamics (SPH) has been developed and applied to a simulation of flows in small hydropower systems. The simulation of the flow through a gravitational vortex turbine (GVT) small hydropower system where the flow is directed to a circular basin with a vertical-axis turbine, harnessing the rotational energy of the vortex formed to drive the turbine. Two modes of Fluid-Structure Interactions (FSI) were tested with identical flow conditions to evaluate the potential of this method to simulate complex FSI scenarios. It was found that simulation results for both one-way and two-way interactions produced reasonable results. The two-way interaction result proved to reflect more accurate FSI scenarios, but more studies are needed to provide validation.

Major merging of galaxies in multicomponent numerical models: mass loss and exchange

The process of collision of two multicomponent galaxies is considered in detail based on numerical simulations of the dynamics of gravitating gas, stars and dark mass. To solve the equations of motion of the gas component, we use the Smoothed Particle Hydrodynamics method. Modeling of collisionless components is based on the N-body model. The computations of gravitational forces are carried out using both the approximate hierarchical TreeCode algorithm and the direct method of summing the gravitational contribution from all particles, which provides an accurate solution. This approach allows testing various models and evaluating the resulting errors associated with the calculation of gravitational forces and a finite number of particles in each of the components. Both methods for calculating gravity are software implemented as parallel codes for Nvidia Tesla GPUs. The estimates of the lost mass and the efficiency of matter exchange between galaxies are discussed depending on the model parameters.

Smoothed particle hydrodynamics method for numerical solution of multidimensional filtering problems

The paper is devoted to solving the filtering problem for a mixture of water, gas, and oil in a homogeneous porous medium. The basic equations of filtration theory are converted into a special form for the numerical approximation with the smoothed particle hydrodynamics (SPH) method. A numerical difference scheme is constructed on the basis of SPH method. An algorithm for setting the boundary conditions is proposed and a number of isothermal 1D and 2D tests on the filtering process simulation for a mixture of water, oil, and gas.

Numerical experimental comparison of mudflow by smoothed particle hydrodynamics (SPH)

Flow-like landslides are a serious geologic hazard that can cause life and property loss all over the world. Mudflow is a kind of debris flow that has been classified as a non-Newtonian flow. The Smoothed particle hydrodynamics method (SPH) is a powerful tool for modeling fluids, such as debris/mudflows, which can be described in terms of local interactions of their constituent parts. In this paper, the Herschel-Buckley rheology model and SPH are used to simulate free-surface mudflow under the gate. The run-out distance and velocity of mudflow during the time are calculated with numerical simulation and compared with the laboratory result. Our results indicate the rate of increase of run-out and viscosity in the computer model is more than the experimental model and it is because of friction that is assumed to be zero. In the computer simulation, friction is exactly zero but in the experimental model, it could be measured and assumed zero. Finally, Abacus had a good result and can be used for mudflow simulation and protection of run-out distance and viscosity.

A Numerical Validation of 3D Experimental Dam-Break Wave Interaction with a Sharp Obstacle Using DualSPHysics

The presence downstream of a dam of either rigid or erodible obstacles may strongly affect the flood wave propagation, and this complex interaction may lead to further dramatic consequences on people and structures. The open-source Lagrangian-based DualSPHysics solver was used to simulate a three-dimensional dam-break in a closed domain including an oriented obstacle that deflects the flow, thus increasing the complexity of fluid dynamics. By comparing numerical results with experimental data, the effectiveness of the model was evaluated and demonstrated with an extensive sensitivity analysis based on several parameters crucial to the smoothed particle hydrodynamics method, such as the resolution, the boundary conditions, and the properties of the interaction weight function. Charts and summary tables highlight the most suitable conditions for simulating such occurrences in the DualSPHysics framework. The presence of the obstacle, being also an opportunity for observation and study of complex fluid dynamics, opens the way to investigate the fluid interaction with solid objects involved in dam-break events and, possibly, to predict their effect with respect to the relative position between them and the flood and other relevant parameters. Finally, the numerical model presents a good overall agreement.

Study of Explosive Welding of A6061/sus821l1 Using Interlayers With Different Thicknesses and the Air Shockwave Between Plates

In this work, interlayers with different thickness were used to weld A6061 aluminum alloy and SUS 821L1 duplex stainless steel. The results indicated that the interlayer thickness had a significant effect on the welding. The influence of the air shock wave between the plates on the welding results was examined. The fluid-Solid coupling finite element method was used to simulate the movement of the interlayer under the action of the air shock wave. The smoothed particle hydrodynamics method was used to simulate the oblique impact process of the plates, and the unwelded samples were analyzed using the simulation results. In the analysis of weldability window, the influence of the interlayer on the upper and lower limits was examined.