Three-dimensional Numerical Analysis of Micro Multiphase Flow Using MPS Method

The aim of this paper is to present an application of high-order numerical analysis methods to a simulation system that models the movement of a cylindrical-shaped object (mine, projectile, etc.) in a marine environment and in general in fluids with important applications in Naval operations. More specifically, an alternative methodology is proposed for the dynamics of the Navy’s three-dimensional mine impact burial prediction model, Impact35/vortex, based on the Dormand–Prince Runge–Kutta fifth-order and the singly diagonally implicit Runge–Kutta fifth-order methods. The main aim is to improve the time efficiency of the system, while keeping the deviation levels of the final results, derived from the standard and the proposed methodology, low.

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Air Ventilation Performance of School Classrooms with Respect to the Installation Positions of Return Duct

Sustainability ◽

10.3390/su13116188 ◽

2021 ◽

Vol 13 (11) ◽

pp. 6188

Author(s):

Sungwan Son ◽

Choon-Man Jang

Keyword(s):

Air Quality ◽

Numerical Analysis ◽

Indoor Air Quality ◽

Indoor Air ◽

Three Dimensional ◽

Cross Infection ◽

School Students ◽

Height Range ◽

Air Ventilation ◽

Ventilation Performance

For students, who spend most of their time in school classrooms, it is important to maintain indoor air quality (IAQ) to ensure a comfortable and healthy life. Recently, the ventilation performance for indoor air quality in elementary schools has emerged as an important social issue due to the increase in the number of days of continuous high concentrations of particulate matter. Three-dimensional numerical analysis has been introduced to evaluate the indoor airflow according to the installation location of return diffusers. Considering the possibility of the cross-infection of infectious diseases between students due to the direction of airflow in the classroom, the airflow angles of the average respiratory height range of elementary school students, between 1.0 and 1.5 m, are analyzed. Throughout the numerical analysis inside the classroom, it is found that the floor return system reduces the indoor horizontal airflow that causes cross-infection among students by 20% compared to the upper return systems. Air ventilation performance is also analyzed in detail using the results of numerical simulation, including streamlines, temperature and the age of air.

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Numerical Analysis of Acoustical Propagation Characteristics in Central Equatorial Pacific Ocean with Ridges of Seabed Used by Three-Dimensional Parabolic Equation Method

Japanese Journal of Applied Physics ◽

10.1143/jjap.39.3212 ◽

2000 ◽

Vol 39 (Part 1, No. 5B) ◽

pp. 3212-3215 ◽

Cited By ~ 4

Author(s):

Takenobu Tsuchiya ◽

Takashi Okuyama ◽

Nobuyuki Endoh ◽

Toshiaki Nakamura ◽

Iwao Nakano

Keyword(s):

Parabolic Equation ◽

Numerical Analysis ◽

Pacific Ocean ◽

Three Dimensional ◽

Equatorial Pacific ◽

Equation Method ◽

Propagation Characteristics ◽

Equatorial Pacific Ocean ◽

Parabolic Equation Method ◽

Central Equatorial Pacific

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Three-dimensional numerical analysis of diffusion current and quantum efficiency of small area Hg1-xCdxTe photodiodes

10.1109/iedm.1981.190029 ◽

1981 ◽

Cited By ~ 1

Author(s):

R.J. Briggs

Keyword(s):

Numerical Analysis ◽

Quantum Efficiency ◽

Small Area ◽

Three Dimensional ◽

Diffusion Current

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Development and Validation of a Three-Dimensional Multiphase Flow CFD Analysis for Journal Bearings in Steam and Heavy Duty Gas Turbines

Volume 7: Structures and Dynamics, Parts A and B ◽

10.1115/gt2012-68201 ◽

2012 ◽

Cited By ~ 2

Author(s):

Stephan Uhkoetter ◽

Stefan aus der Wiesche ◽

Michael Kursch ◽

Christian Beck

Keyword(s):

Experimental Data ◽

Multiphase Flow ◽

Gas Turbines ◽

High Speed ◽

Three Dimensional ◽

Air Entrainment ◽

Journal Bearings ◽

Heavy Duty ◽

Present Contribution ◽

Two Phase

The traditional method for hydrodynamic journal bearing analysis usually applies the lubrication theory based on the Reynolds equation and suitable empirical modifications to cover turbulence, heat transfer, and cavitation. In cases of complex bearing geometries for steam and heavy-duty gas turbines this approach has its obvious restrictions in regard to detail flow recirculation, mixing, mass balance, and filling level phenomena. These limitations could be circumvented by applying a computational fluid dynamics (CFD) approach resting closer to the fundamental physical laws. The present contribution reports about the state of the art of such a fully three-dimensional multiphase-flow CFD approach including cavitation and air entrainment for high-speed turbo-machinery journal bearings. It has been developed and validated using experimental data. Due to the high ambient shear rates in bearings, the multiphase-flow model for journal bearings requires substantial modifications in comparison to common two-phase flow simulations. Based on experimental data, it is found, that particular cavitation phenomena are essential for the understanding of steam and heavy-duty type gas turbine journal bearings.

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