Numerical modeling of cough airflow: Establishment of spatial–temporal experimental dataset and CFD simulation method

2021 ◽  
pp. 108531
Author(s):  
Wonseok Oh ◽  
Ryozo Ooka ◽  
Hideki Kikumoto ◽  
Mengtao Han
Keyword(s):  
Numerical Modeling ◽  
Cfd Simulation ◽  
Simulation Method ◽  
Experimental Dataset ◽  
Cough Airflow

Research on CFD Simulation of the Cement Slurry Mixer

2012 ◽  
Vol 621 ◽  
pp. 196-199
Author(s):  
Shui Ping LI ◽  
Ya Li Yuan ◽  
Lu Gang Shi
Keyword(s):  
Flow Field ◽  
High Performance ◽  
Cfd Simulation ◽  
Structural Parameters ◽  
Internal Flow ◽  
Simulation Method ◽  
Cement Slurry ◽  
Fluid Machinery ◽  
Computational Fluid Dynamics Cfd ◽  
Machinery Design

Numerical simulation method of the internal flow field of fluid machinery has become an important technology in the study of fluid machinery design. In order to obtain a high-performance cement slurry mixer, computational fluid dynamics (CFD) techniques are used to simulate the flow field in the mixer, and the simulation results are studied. According to the analysis results, the structural parameters of the mixer are modified. The results show the mixer under the revised parameters meet the design requirements well. So CFD analysis method can shorten design period and provide valuable theoretical guidance for the design of fluid machinery.

Thorough Verification and Validation of CFD Simulation for FPSO Roll Damping

2019 ◽  
Author(s):  
Donghwan Lee ◽  
Zhenjia (Jerry) Huang
Keyword(s):  
Numerical Modeling ◽  
Cfd Simulation ◽  
Development Project ◽  
Model Tests ◽  
Design Tool ◽  
Verification And Validation ◽  
Empirical Formulas ◽  
Roll Damping ◽  
Calm Water ◽  
Offshore Industry

Abstract For floating production platform such as FPSO and FLNG, it is important to use confidently estimated roll damping coefficients in the prediction of its motions in waves since in many cases the roll response is mainly contributed from resonance. Traditionally roll damping prediction was made through model tests or empirical formulas. As computing power and numerical modeling techniques have been improved during last a few decades, offshore industry starts to consider CFD as an alternative engineering and design tool complementary and/or supplementary to physical model tests. This paper presents our verification and validation work of modeling practices with commercially available CFD software for engineering applications for FPSO roll decay damping in calm water. The numerical modeling followed a recommended modeling practice developed by a Joint Development Project – TESK JDP [1].

A Time-Parallel CFD Approach for Unsteady Combustor Flow Analysis and Design Optimization

2012 ◽  
Author(s):  
Moresh J. Wankhede ◽  
Neil W. Bressloff ◽  
Andy J. Keane
Keyword(s):  
Flow Field ◽  
Domain Decomposition ◽  
Design Optimization ◽  
Cfd Simulation ◽  
Simulation Method ◽  
Spatial Domain ◽  
Parallel Simulation ◽  
Analysis And Design ◽  
Temporal Domain ◽  
Parallel Cfd

Computational fluid dynamics (CFD) simulations to predict and visualize the reacting flow dynamics inside a combustor require fine resolution over the spatial and temporal domain, making them computationally very expensive. The traditional time-serial approach for setting up a parallel combustor CFD simulation is to divide the spatial domain between computing nodes and treat the temporal domain sequentially. However, it is well known that spatial domain decomposition techniques are not very efficient especially when the spatial dimension (or mesh count) of the problem is small and a large number of nodes are used, as the communication costs due to data parallelism becomes significant per iteration. Hence, temporal domain decomposition has some attraction for unsteady simulations, particularly on relatively coarse spatial meshes. The purpose of this study is two-fold: (i), to develop a time-parallel CFD simulation method and apply it to solve the transient reactive flow-field in a combustor using an unsteady Reynolds-averaged Navier Stokes (URANS) formulation in the commercial CFD code FLUENT™ and (ii) to investigate its benefits relative to a time-serial approach and its potential use for combustor design optimization. The results show that the time-parallel simulation method correctly captures the unsteady combustor flow evolution but, with the applied time-parallel formulation, a clear speed-up advantage, in terms of wall-clock time, is not obtained relative to the time-serial approach. However, it is clear that the time-parallel simulation method provides multiple stages of transient combustor flow-field solution data whilst converging towards a final converged state. The availability of this resulting data could be used to seed multiple levels of fidelity within the framework of a multi-fidelity co-Kriging based design optimization strategy. Also, only a single simulation would need to be setup from which multiple fidelities are available.

Numerical Simulation of Real-Gas Flow in a Supersonic Turbine Nozzle Ring

2002 ◽  
Vol 124 (2) ◽  
pp. 395-403 ◽  
Author(s):  
J. Hoffren ◽  
T. Talonpoika ◽  
J. Larjola ◽  
T. Siikonen
Keyword(s):  
Power Plants ◽  
Gas Flow ◽  
Cfd Simulation ◽  
Low Cost ◽  
Design Procedure ◽  
Rankine Cycle ◽  
Simulation Method ◽  
Ideal Gas ◽  
Working Fluid ◽  
Real Gas

In small Rankine cycle power plants, it is advantageous to use organic media as the working fluid. A low-cost single-stage turbine design together with the high molecular weight of the fluid leads to high Mach numbers in the turbine. Turbine efficiency can be improved significantly by using an iterative design procedure based on an accurate CFD simulation of the flow. For this purpose, an existing Navier-Stokes solver is tailored for real gas, because the expansion of an organic fluid cannot be described with ideal gas equations. The proposed simulation method is applied for the calculation of supersonic flow in a turbine stator. The main contribution of the paper is to demonstrate how a typical ideal-gas CFD code can be adapted for real gases in a very general, fast, and robust manner.

scholarly journals A Spatially Distributed Network for Tracking the Pulsation Signal of Flow Field Based on CFD Simulation: Method and a Case Study

2021 ◽  
Vol 5 (4) ◽  
pp. 181
Author(s):  
Faye Jin ◽  
Ran Tao ◽  
Zhaoheng Lu ◽  
Ruofu Xiao
Keyword(s):  
Vortex Shedding ◽  
Frequency Conversion ◽  
Cfd Simulation ◽  
Simulation Method ◽  
Time Frequency ◽  
Flow Problems ◽  
Spatially Distributed ◽  
Edge Vortex ◽  
Vortex Shedding Frequency ◽  
Temporal And Spatial Characteristics

The pulsating characteristics in turbulent flow are very important physical quantities. There are many studies focused on the temporal characteristics of pulsation. However, the spatial distribution of temporal states with pulsations rarely receives attention. Therefore, the pulsation tracking network (PTN) method is proposed to track the pulsating characteristics of turbulence. Based on the computational fluid dynamics (CFD) simulation result, the PTN is arranged in a specific region of the flow domain. The fast Fourier Transform (FFT) method is used for time-frequency conversion. As shown in the example of trailing-edge vortex-shedding flow over NACA0009 hydrofoil, important pulsation quantities, including the total pulsation intensity, dominant frequencies, amplitude of frequencies, and the phase and phase difference, can be obtained with a high spatial resolution. The source, reason and attenuation of the vortex-shedding frequency fvs and the 2 fvs frequency caused by vortex-interaction are well indicated. The dominant regions of fvs and 2 fvs are shown and analysed. The propagation and attenuation of vortex-shedding induced pulsation are understood in detail. Based on the comparison against traditional analysis, PTN is found to function as a good supplement for the CFD post-processing by tracking unknown temporal and spatial characteristics. These findings represent a potential breakthrough in terms of solving actual pulsation-excited flow problems.

Calibration of the CFD code based on testing of a standard AGARD-B model for determination of aerodynamic characteristics

2020 ◽  
pp. 095441002096685
Author(s):  
Čedomir Kostić ◽  
Aleksandar Bengin ◽  
Boško Rašuo ◽  
Dijana Damljanović
Keyword(s):  
Cfd Simulation ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Advisory Group ◽  
Test Model ◽  
Computational Domain ◽  
Technical Institute ◽  
Strong Point ◽  
Wide Range

The goal of this work is to build a unique numerical method to obtain the basic aerodynamic characteristics of the aircraft and to enable a wide application of the method in the analysis of some aerodynamic characteristics of the aircraft, without use of empirical methods. The Computational fluid dynamics (CFD) simulation method was being calibrated based on test results of the standard AGARD-B (Advisory Group for Aerospace Research and Development) test model, which were obtained in the T-38 trisonic wind tunnel facility of the Military Technical Institute (VTI) in Belgrade, Serbia.The paper presents the CFD simulation through a description of the conditions of flow, geometry of the computer domain, grid density and mesh strategy, boundary conditions, initial strategy and turbulence model. The CFD simulation was carried out for flow cases with similarity parameters M = 0.6, M = 0.85 and M = 1.6 and Re = from 7.7(x106) to 9.9(x106) . The results of calculations were compared with the appropriate experimental ones and presented in the form of comparative diagrams for the drag, lift and pitching moment coefficients. The results of investigation presented in divergence diagrams show very good agreement between numerical and experimental ones. Simulated flows are illustrated by the distribution of pressure and velocity components on the surface of the tested model and the computational domain. This CFD simulation will be applied to other similar aerodynamic designs for a wide range angles of attack and Mach numbers and can be a strong point for the development of different aerodynamic designs.The ultimate aim of the work is to use the previous calibrated CFD simulation method as the basis for future determination of the aerodynamic characteristics of aircraft in non-stationary flight modes, caused by motion of the aircraft and/or by changing the free-velocity vector.

scholarly journals CFD Simulation of the Wind Field in Jinjiang City Using a Building Data Generalization Method

Atmosphere ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 326 ◽  
Author(s):  
Mengxi Li ◽  
Xinfa Qiu ◽  
Juanjun Shen ◽  
Jinqin Xu ◽  
Bo Feng ◽  
...  
Keyword(s):  
Wind Field ◽  
Cfd Simulation ◽  
Field Research ◽  
Simulation Method ◽  
Geographic Information ◽  
Measured Data ◽  
Computer Hardware ◽  
Gis Technology ◽  
Data Generalization ◽  
Simulated Wind

The urban wind environment is an important element of urban microclimates and plays an important role in the quality of the urban environment. The computational fluid dynamics (CFD) simulation method is an important means for urban wind field research. However, CFD simulation has high requirements for computer hardware and software. In this paper, based on geographic information system (GIS) technology, a new building data generalization method was developed to solve the problems of a huge amount of data and calculations in urban-scale CFD wind field simulations. Using Fluent software and high-precision urban building geographic information data with elevation attributes, the method was applied to Jinjiang City, Fujian Province, China. A CFD simulation of the wind field of Jinjiang City was implemented, and detailed, intuitive wind field information was obtained, which were compared with the measured data. The results show that the building data generalization method could effectively improve the efficiency of the city's overall wind field CFD simulation. The simulated wind speed was significantly correlated with the measured data, but it was overestimated. The simulated wind direction was consistent with the measured data of most stations. The simulation results were reasonable and could provide reference for application and subsequent research.

Optimze the Structure of Impeller for Stirred Bioreactor

2013 ◽  
Vol 694-697 ◽  
pp. 148-153 ◽  
Author(s):  
Li Kuan Zhu ◽  
Bo Yan Song ◽  
Zhen Long Wang ◽  
Yu Kui Wang
Keyword(s):  
Fluid Dynamics ◽  
Flow Field ◽  
Shear Force ◽  
Large Scale ◽  
Cfd Simulation ◽  
Simulation Method ◽  
Stirred Bioreactor ◽  
Anticlockwise Rotation ◽  
Computational Fluid Dynamics Cfd ◽  
Large Scale Culture

This paper mainly makes comparative analysis on four main types of blade in stirred bioreactor by Computational Fluid Dynamics(CFD) simulation. Firstly we establish simulation method suited for stirred bioreactor, then simulate the velocity and shear force of flow field in the bioreactor. No matter from flow field mixing or shear force aspect, Elephant Ear blades is the most suitable for cell large scale culture. At last, it optimizes the installation method and angle of Elephant Ear blades. It concludes that anticlockwise rotation and 45°installation angle is the optimum.

Effect Analysis of Different Exhaust Velocity on Fire Smoke Control in Subway Tunnel

2012 ◽  
Vol 424-425 ◽  
pp. 1224-1227
Author(s):  
Xin Han ◽  
Xiao Ming Gao ◽  
Bei Hua Cong
Keyword(s):  
Cfd Simulation ◽  
Simulation Analysis ◽  
Simulation Method ◽  
Subway Tunnel ◽  
Control Effect ◽  
Smoke Control ◽  
Effect Analysis ◽  
Longitudinal Ventilation ◽  
Fire Smoke ◽  
Ventilation Velocity

Taking a subway tunnel as the research object and based on the CFD simulation method, this paper adopts a large eddy simulation analysis software FDS to simulate and analyze the effect of exhaust velocity on fire smoke control under the condition of the same longitudinal ventilation velocity in subway tunnel. The simulated results can provide some reference to design institutes in the selection of exhaust fan. While the longitudinal ventilation velocity set as 1m/s, the simulation results demonstrate that a quite good smoke control effect could be achieved when the exhaust velocity reaches 5 m/s in the smoke exhaust duct

Prediction of the Flow Coefficient of a PFA Lined Ball Valve Using the CFD Simulation Method

2016 ◽  
Vol 19 (4) ◽  
pp. 35-38
Author(s):  
Hong-Pil Jeon ◽  
Won-Seob Lee ◽  
Chul-Soo Kim ◽  
Jong-Chul Lee
Keyword(s):  
Cfd Simulation ◽  
Simulation Method ◽  
Ball Valve ◽  
Flow Coefficient
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