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Optimizing Speedup Performance of computational Hydrodynamic Simulations with UPC Programming Model

JOURNAL OF COMPUTING IN CIVIL ENGINEERING 2020年第2期34卷

作者： Chew, Alvin Wei Ze Law, Adrian Wing-Keung Tung Thanh Vu Nanyang Technol Univ Sch Civil & Environm Engn N1-01c-9850 Nanyang Ave Singapore 639798 Singapore Nanyang Technol Univ Nanyang Environm & Water Res Inst Environm Proc Modelling Ctr 1 Cleantech LoopCleanTech One06-08 Singapore 637141 Singapore Rikkeisoft 21st FloorHandico TowerPham Hung St Hanoi Vietnam

In this study, we exploit the advantages of Berkeley's Unified Parallel C (UPC) programming model to optimize the speedup performance of computational hydrodynamic (CHD) simulations, which constitute an important class of modelling tool for hydraulic engineering applications. A two-dimensional (2D) numerical model, termed UPC-CHD, is developed using the conservative forms of the Navier-Stokes (NS) continuity, momentum, and energy equations for viscous, incompressible, and adiabatic flow cases with the UPC model. The following numerical schemes are adopted for discretization in UPC-CHD: (1) a 2-step Lax-Wendroff explicit scheme for the temporal term;(2) a Roe linear approximation with a 3rd-order upwind biased algorithm for the convective fluxes;and (3) a central-differencing scheme for the viscous fluxes. The obtained speedup results demonstrate that UPC-CHD with the affinity principle achieves good speedup performance when compared to the serial algorithm, with an average value of 0.8 per unit core (thread) until 100 processor cores when simulating the Couette, Blasius boundary layer, and Poiseuille flows on a 2D domain of 100 million grids. Finally, we also investigate the effects of varying domain size on the speedup performances of UPC-CHD for the same flow conditions.

关键词： Parallel computing computational hydrodynamics Viscous and incompressible flows Partitioned global address space (PGAS) Unified parallel computing (UPC)

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Mathematical Simulation of the Swirling Flow of a Thermoviscous, Pseudoplastic Sisco Fluid in a Cylindrical Channel

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JOURNAL OF ENGINEERING PHYSICS AND THERMOPHYSICS 2020年第4期93卷 827-838页

作者： Matvienko, O. V. Aseeva, A. E. Natl Res Tomsk State Univ 36 Lenin Ave Tomsk 634050 Russia Tomsk State Univ Architecture & Civil Engn 2 Solyanaya Sq Tomsk 634003 Russia

The swirling flow of a thermoviscous, pseudoplastic Sisco fluid in a cylindrical channel was investigated. It was established that, in the case of irrotational flow of a pseudoplastic fluid in such a channel, the effective viscosity of the fluid in the neighborhood of the channel axis is substantially increased. A swirling of this flow leads to an increase in the rate of shear deformation of the fluid in the axial region of the flow and to a decrease in its effective viscosity. As the swirling of the flow in the channel increases, the fluid near the channel walls and the fluid at the boundary of the recirculation zone are subjected to a dissipative heating leading to a decrease in their effective viscosity. The intensity heating of the fluid in the channel increases with increase in the rate of swirling (the Rossby number) of its flow.

关键词： rheology non-Newtonian fluid thermoviscous fluid pseudoplastic Sisco fluid heat exchange swirling flow viscous dissipation computational hydrodynamics

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Numerical analysis of the installation procedures of offshore structures

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OCEAN ENGINEERING 2019年 179卷 116-127页

作者： Luo-Theilen, Xiaojing Rung, Thomas Hamburg Univ Technol Inst Fluid Dynam & Ship Theory Hamburg Germany

The paper is concerned with the simulation of grounding of gravity foundations for wind turbines and the installation process of jack-up rigs in seaway. They are of particular interest for offshore wind parks, where numerical investigations can support the safety margins of an operation. The computational focus of the present study is to supplement a viscous three-phase fluid-soil solver for overset grids by appropriate mechanical models to analyse the dynamics of such complex systems. A quaternion-based motion modeller featuring several basic joint elements is used to model the mechanical interaction between different parts of a structure, which can be seen as a multi-body system. Examples included refer to simpler validation cases and generic, nonetheless realistic applications, which aim to illustrate the predictive capabilities of the procedure.

关键词： Jack-up rigs Gravity foundation Coupled bodies Mechanical joints Seaway computational hydrodynamics

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MATHEMATICAL MODELING OF SWIRLING HERSCHEL-BULKLEY PSEUDOPLASTIC FLUID FLOW IN A CYLINDRICAL CHANNEL

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JOURNAL OF ENGINEERING PHYSICS AND THERMOPHYSICS 2019年第1期92卷 208-218页

作者： Matvienko, O., V Bazuev, V. P. Aseeva, A. E. Natl Res Tomsk Polytech Univ 30 Lenin Ave Tomsk 634050 Russia Tomsk State Univ Architecture & Civil Engn 2 Solyanaya Sq Tomsk 634003 Russia

Results of investigations into the swirling flow of a pseudoplastic fluid with a Herschel-Bulkley yield stress in a cylindrical channel have been presented. It has been established that a growth in the rates of shear strains inflows with a swirl causes the values of effective viscosity to decrease. It has been shown that at one and the same Rossby number, the recirculation strength is the greater the smaller the values of the limiting shear stress, the consistency, and the nonlinearity index.

关键词： rheology pseudoplastic media viscoplastic fluid Herschel-Bulkley fluid swirling flows computational hydrodynamics

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Mathematical Simulation of the Swirling Flow of a Dilatant Herschel-Bulkley Fluid in a Cylindrical Channel

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JOURNAL OF ENGINEERING PHYSICS AND THERMOPHYSICS 2019年第6期92卷 1593-1602页

作者： Matvienko, O., V Bazuev, V. P. Aseeva, A. E. Tomsk State Univ 36 Lenin Ave Tomsk 634050 Russia Tomsk State Architecture & Civil Engn Univ 2 Solyanaya Sq Tomsk 634003 Russia

Results of an investigation of the swirling flow of a dilatant Herschel-Bulkley fluid with a yield point in a cylindrical channel are presented. It was established that the effective viscosity of such a fluid at the input cross section of a cylindrical channel increases with increase in the intensity of its vortex, which can cause plugging of the channel. As the Rossby number of this fluid increases, its effective viscosity in the region of unstable flow at the axis of the channel decreases, and the opposite effect takes place in the near-wall zone of the channel. As the fluid flow stabilizes downstream, the effective viscosity of the fluid in the near-wall region of the channel decreases, and the effective viscosity of the fluid near the channel axis increases, which leads to the formation of a quasi-solid fluid flow.

关键词： rheology dilatant fluid viscoplastic fluid Herschel-Bulkley fluid swirling flow computational hydrodynamics

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SEPARATION OF NONSPHERICAL PARTICLES IN A HYDROCYCLONE

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JOURNAL OF ENGINEERING PHYSICS AND THERMOPHYSICS 2018年第3期91卷 712-730页

作者： Matvienko, O., V Andropova, A. O. Tomsk State Univ 36 Lenin Ave Tomsk 634036 Russia Tomsk State Architecture & Civil Engn Univ 2 Solyanaya Sq Tomsk 634003 Russia

On the basis of hydrodynamic equations, the structure of the flow of a suspension in a hydrocyclone and the separation of isothermal nonspherical particles in it were investigated numerically. A mathematical model is proposed for calculating the separation parameters of the indicated particles and their concentration field. It is shown that the most marked dependence of the separation parameters of suspension particles on their shape is characteristic of the particles whose sizes fall within the range 10 < d(p) < 50 pm and that the separation of such particles should be conducted taking into account the possible deviation of their shape from the spherical one.

关键词： hydrocyclone separation multiphase turbulent flows computational hydrodynamics

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Fully Automated Ship Resistance Prediction Using the Naval Hydro Pack 19

Fully Automated Ship Resistance Prediction Using the Naval H...

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19th International Conference on Ships and Maritime Research (NAV)

作者： Gatin, Inno Vukocvic, Vuko Skuric, Vanja Jasak, Hrvoje Univ Zagreb Fac Mech Engn & Naval Architecture Zagreb Croatia

ISBN: (纸本)9781614998709;9781614998693

A numerical environment for efficient assessment of ship resistance using CFD is presented in this paper. Predicting ship resistance in calm water with the Naval Hydro Pack can be performed within a few hours, including grid generation, computation and post processing of results. Being able to rapidly predict ship resistance renders CFD a cost-effective design tool, since a hull form designer can evaluate multiple variants of hull geometry quickly. The process of setting up, running and post-processing is accelerated by automating the process to a high level, significantly decreasing the number of manual work effort. In this paper the capabilities of the Naval Hydro Pack are demonstrated by calculating steady resistance for three different benchmark hull forms, where time for pre-processing, processing and post-processing is reported. On average, it took two and a half hours to obtain steady state results per hull form, including set up, computational time and data analysis. Results are validated against available experimental data showing accuracy with errors below 4%, which is acceptable for early design stage.

关键词： Steady Resistance computational hydrodynamics CFD Naval Hydro Pack

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Using adaptive nested mesh code HydroBox3D for numerical simulation of Type Ia supernovae: merger of carbon-oxygen white dwarf stars, collapse, and non-central explosion

Using adaptive nested mesh code HydroBox3D for numerical sim...

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Ivannikov Ispras Open Conference (ISPRAS)

作者： Kulikov, Igor Chernykh, Igor Karavaev, Dmitry Protasov, Victor Serenko, Alexander Prigarin, Vladimir Ulyanichev, Ivan Tutukov, Alexander RAS ICMMG SB Novosibirsk Russia RAS Inst Astron Moscow Russia

ISBN: (纸本)9781728112756

The paper presents the results of mathematical modeling of the three main stages of the explosion of supernovae of type la (SNIa): merging of white dwarfs, collapse and noncentral explosion. In the fusion problem shown the general fall mechanism of the satellite star onto the central star. At the modeling of the collapse process, the behavior of various types of energies is investigated. Also shown is the qualitative dynamics of a noncentral of a star explosion, whose source is the characteristic value of the energy released by the reaction C + C. The simulation was carried out using the original HydroBox3D code, in which the concept of adaptive nested mesh is implemented.

关键词： Adaptive nested mesh computational hydrodynamics Computation Astrophysics Numerical simulation SNIa

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Responses of Bed Morphology to Vegetation Growth and Flood Discharge at a Sharp River Bend

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WATER 2018年第2期10卷 223页

作者： Kang, Taeun Kimura, Ichiro Shimizu, Yasuyuki Hokkaido Univ Hydraul Res Lab Sapporo Hokkaido 0608628 Japan

In this study, we conducted simulations using a two-dimensional, depth-averaged river flow and river morphology model to investigate the effect of vegetation growth and degree of flow discharge on a shallow meandering channel. To consider the effects of these factors, it was assumed that vegetation growth stage is changed by water flow and bed erosion. The non-uniformity of the vegetation growth was induced by the non-uniform and unsteady profile of the water depth due to the irregular shape of the bed elevation and the unsteady flow model reliant on hydrographs to evaluate three types of peak discharges: moderate flow, annual average maximum flow, and extreme flow. To compare the effects of non-uniform growing vegetation, the change in channel patterns was quantified using the Active Braiding Index (ABI), which indicates the average number of channels with flowing water at a cross section and the Bed Relief Index (BRI), which quantifies the degree of irregularity of the cross-sectional shape. Two types of erosion were identified: local erosion (due to increased flow velocity near a vegetation area) and global erosion (due to the discharge approaching peak and the large depth of the channel). This paper demonstrated that the growth of vegetation increases both the ABI and BRI when the peak discharge is lower than the annual average discharge, whereas the growth of vegetation reduces the BRI when the peak discharge is extreme. However, under extreme discharge, the ABI decreases because global erosion is dominant. The conclusions from this study help to deepen the understanding of the interactions between curved river channels and vegetation.

关键词： river bed morphology sharp river bend vegetation 2-D shallow flow model computational hydrodynamics

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Experimental and numerical simulation of interphase mass transfer of gas bubble in granular backfill and gel

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THEORETICAL FOUNDATIONS OF CHEMICAL ENGINEERING 2016年第5期50卷 690-696页

作者： Pokusaev, B. G. Nekrasov, D. A. Karlov, S. P. Khramtsov, D. P. Moscow State Engn Univ Moscow Russia

An experimental and numerical study of the process of interphase mass transfer has been performed upon the motion of gas bubble in the granular layer saturated with liquid at different tilt angles of the tube and in the case of movement in the channel between the gel layers. The dependences of the coefficient of effective dimensionless mass transfer have been obtained depending on the tilt angle of the tube and backfill diameter. The relationship between the coefficient of effective dimensionless mass transfer and the rate of the free-floating gas bubble has been established.

关键词： mass transfer granular medium multiphase flows computational hydrodynamics gel

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