The Performance Analysis of the Thermal Discrete Element Method Computations on the GPU

The paper presents a GPU implementation of the thermal discrete element method (TDEM) and the comparative analysis of its performance. Several discrete element models for granular flows, the bonded particle model and the TDEM are considered for quantitative comparison of computational performance. The performance measured on NVIDIA(R) Tesla™ P100 GPU is compared with that attained by running the same OpenCL code on Intel(R) Xeon™ E5-2630 CPU with 20 cores. The presented GPU implementation of the TDEM increases the computing time of the bonded particle model only up to 30.6 % of the computing time of the simplest DEM model, which is an acceptable decrease in the performance required for solving coupled thermomechanical problems

Global optimization of grillages using simulated annealing and high performance computing

The aim is to investigate ways of increasing the efficiency of grillage optimization. Following this general aim, two well‐known optimization methods, namely the Genetic Algorithm (GA) and Simulated Annealing (SA), were compared using some standard medium size (10 and 15 piles) examples. The objective function was the maximal vertical reactive force at a support. Coordinates of piles were optimization variables. SA wins and was applied to real‐life problem (55 piles) by parallel computations performed using a powerful cluster. New element is comparison of SA with GA and application of SA to a practical problem of grillage optimization. Santrauka Straipsnio tikslas ‐ ištirti galimus rostverkiniu pamatu optimizavimo būdus. Siekiant šio tikslo du gerai žinomi optimizavimo metodai ‐ genetiniai algoritmai ir atkaitinimo modeliavimo algoritmas ‐ buvo palyginti vidutinio dydžio (10 ir 15 poliu) pavyzdžiams išspresti. Tikslo funkcija imama didžiausia atraminI poliaus reakcija. Projektavimo kintamieji ‐ poliu koordinatIs. Atkaitinimo modeliavimo metodas laimi, todel jis buvo pritaikytas praktiniam uždaviniui (55 poliai) spresti. Spresti buvo naudojamas klasteris. Naujumas ‐ genetiniu algoritmu palyginimas su atkaitinimo modeliavimo metodu bei atkaitinimo modeliavimo metodo pritaikymas sprendžiant praktini uždavini. Published Published Online: 14 Oct 2010 Reikšminiai žodžiai: rostverkai, atkaitinimo modeliavimas, globalus optimizavimas, baigtiniai elementai, genetiniai algoritma

Performance Evaluation of Parallel Haemodynamic Computations on Heterogeneous Clouds

The article presents performance evaluation of parallel haemodynamic flow computations on heterogeneous resources of the OpenStack cloud infrastructure. The main focus is on the parallel performance analysis, energy consumption and virtualization overhead of the developed software service based on ANSYS Fluent platform which runs on Docker containers of the private university cloud. The haemodynamic aortic valve flow described by incompressible Navier-Stokes equations is considered as a target application of the hosted cloud infrastructure. The parallel performance of the developed software service is assessed measuring the parallel speedup of computations carried out on virtualized heterogeneous resources. The performance measured on Docker containers is compared with that obtained by using the native hardware. The alternative solution algorithms are explored in terms of the parallel performance and power consumption. The investigation of a trade-off between the computing speed and the consumed energy is performed by using Pareto front analysis and a linear scalarization method

Defining the Minimum Security Baseline in a Multiple Security Standards Environment by Graph Theory Techniques

One of the best ways to protect an organization’s assets is to implement security requirements defined by different standards or best practices. However, such an approach is complicated and requires specific skills and knowledge. In case an organization applies multiple security standards, several problems can arise related to overlapping or conflicting security requirements, increased expenses on security requirement implementation, and convenience of security requirement monitoring. To solve these issues, we propose using graph theory techniques. Graphs allow the presentation of security requirements of a standard as graph vertexes and edges between vertexes, and would show the relations between different requirements. A vertex cover algorithm is proposed for minimum security requirement identification, while graph isomorphism is proposed for comparing existing organization controls against a set of minimum requirements identified in the previous step

On Efficiency of Parallel Solvers for the Blood Flow through Aortic Valve

Mathematical modelling of cardiac haemodynamics presents a great challenge to the computational scientists due to numerous numerical issues and required computational resources. In this paper, we study the parallel performance of 3D simulation software for the blood flow through the aortic valve. The fluid flow problem with the open aortic valve leaflets is formulated and solved in parallel. The choice between the segregated and coupled numerical schemes is discussed and investigated. We present and compare the parallel performance results of both types of parallel solvers. We investigate their strong and weak scalability

Dam break flow simulation by the pseudo-concentration method

In this paper, dam break flow simulation is performed by the finite elements and the pseudo-concentration method. Solution domain is discretized by the space-time finite elements, while numerical schemes are stabilised by the Galerkin least squares method. The moving interface is modelled by the pseudo-concentration method and the simple interface reconstruction technique. Several cases of the broken dam problem are solved in order validate the numerical approach. The computed values of the reduction of water column height are compared with the experimental measurements. The simulated breaking wave phenomena shows that investigated numerical technique is capable of modelling moving interfaces undergoing large topological changes

Efektyvios paviršiaus rekonstrukcijos procedūros, skirtos klampioms nespūdžioms tėkmėms modeliuoti, kūrimas ir tobulinimas

The paper describes the development of the efficient interface sharpening procedure for viscous incompressible flows governed by the Navier-Stokes equations. The moving interface has been captured by a pseudo-concentration method. The solution domain has been discretised by the space-time finite elements, while numerical schemes have been stabilised by the Galerkin least squares method. The dam break problem including breaking waves has been solved in order to validate the performance of the numerical technique. The computed position of the leading edge of water column has been compared with the experimental measurements. The detailed investigation of numerical parameters governing the sharpness of the front and mass conservation has been presented.Lietuviška santrauka. Straipsnyje aprašomas efektyvios paviršiaus rekonstrukcijos procedūros, taikomos klampioms nespūdžioms dvipusių paviršių tėkmėms modeliuoti, kūurimas ir tobulinimas. Tėkmė nusakoma Navje ir Stokso lygtimis, o kintantis dvipusis paviršius modeliuojamas pseudokoncentracijos metodu. Uždavinio apibrėžimo sritis diskretizuojama erdvės ir laiko baigtiniais elementais, o skaitinės schemos stabilizuojamos Galiorkino mažiausių kvadratų metodu. Skaitinė procedūra ištestuota sprendžiant sugriuvusios užtvankos uždavinį su lūužtančiomis bangomis. Skaitiniais metodais apskaičiuota sklindančio vandens stulpelio krašto padėtis palyginta su eksperimentinių matavimų rezultatais. Pateikta detali skaitinių parametrų, reguliuojančių dvipusio paviršiaus glodumą ir tėkmės masės tvermę, studija

Mass conservation issues of moving interface flows modelled by the interface capturing approach

The paper describes the development of the mass correction technique for viscous incompressible flows including moving interfaces. The dam break problem is solved by the pseudo-concentration method based on the interface capturing approach. The detailed numerical in-vestigation of the nonlinear solution of the mass conservation equation is presented. The interface sharpening governed by different strategies is examined. The developed mass correction technique is validated on two finite element meshes of different resolution

Dvipusių paviršių tėkmės, modeliuojamos remiantis neišreikštinio paviršiaus koncepcija, masės tvermės problemos

The paper describes the development of the mass correction technique for viscous incompressible flows including moving interfaces. The dam break problem is solved by the pseudo-concentration method based on the interface capturing approach. The detailed numerical in-vestigation of the nonlinear solution of the mass conservation equation is presented. The interface sharpening governed by different strategies is examined. The developed mass correction technique is validated on two finite element meshes of different resolution.Lietuviška santrauka. Straipsnyje pateikiama masės tvermės palaikymo technologija, skirta klampioms nespūdžioms dvipusių paviršių tėkmėms modeliuoti. Sugriuvusios užtvankos uždavinys sprendžiamas pseudokoncentracijos metodu, pagrįstu neišreikštinio paviršiaus koncepcija. Pateikiami detalūs skaitiniai netiesinės masės tvermės lygties sprendimo tyrimai. Nagrinėjamos įvairios paviršiaus rekonstrukcijos valdymo strategijos. Masės tvermės palaikymo technologija testuota dviem skirtingos rezoliucijos baigtinių elementų tinklais