Verification and Validation of CFD Uncertainty Analysis Based on SST K-ω Model

2020 ◽  
Author(s):  
Li Zhang ◽  
Weimin Chen ◽  
Jianting Chen ◽  
Chuanming Zhou
Keyword(s):  
Numerical Simulation ◽  
Uncertainty Analysis ◽  
Cfd Simulation ◽  
Numerical Results ◽  
Verification And Validation ◽  
Ship Model ◽  
The Past ◽  
Mesh Density ◽  
Simulation Results ◽  
Selection Of

Abstract CFD uncertainty analysis is a process to quantify the accuracy of numerical simulation results, and it is also a research hotspot in the past decades. ITTC(2017) requires uncertainty analysis of ship CFD simulation results, that is, verification and validation. In this paper, with reference to the recommended procedures by ITTC, the uncertainty of the CFD numerical simulation results of ship model resistance was analyzed. Based on the SST k-ω turbulence model, the Y+ values near the wall were set to 60,120,240, respectively. And for each and Y+ value, three different sets of grid densities were set respectively, and the uncertainty was analyzed. The results show that: 1) the results of Y+ at 60 and 120 were not validated, and the results at 240 was validated, 2) the selection of Y+ value has a significant effect on the numerical results, 3) increasing the mesh density can make the result converge, but it is not sure to get the result with the least error. Through the uncertainty analysis of CFD results, it is helpful to find a method to improve the accuracy of the numerical results.

scholarly journals The study of the numerical diffusion in computational calculation

2020 ◽  
Vol 310 ◽  
pp. 00039
Author(s):  
Kamila Kotrasova ◽  
Vladimira Michalcova
Keyword(s):  
Heat Transfer ◽  
Differential Equation ◽  
Numerical Simulation ◽  
Continuity Equation ◽  
Cfd Simulation ◽  
Flow Process ◽  
Ansys Fluent ◽  
Numerical Diffusion ◽  
Mesh Density ◽  
Computational Calculation

The numerical simulation of flow process and heat transfer phenomena demands the solution of continuous differential equation and energy-conservation equations coupled with the continuity equation. The choosing of computation parameters in numerical simulation of computation domain have influence on accuracy of obtained results. The choose parameters, as mesh density, mesh type and computation procedures, for the numerical diffusion of computation domain were analysed and compared. The CFD simulation in ANSYS – Fluent was used for numerical simulation of 3D stational temperature flow of the computation domain.

Study on the Principle of Yarn Splicing of Pneumatic Splicer Using Numerical Simulation

2012 ◽  
Vol 588-589 ◽  
pp. 1355-1358
Author(s):  
Xiao Xing ◽  
Guo Ming Ye
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Numerical Results ◽  
Simulation Results

During the splicing process of pneumatic splicer, the principle of yarn splicing is closely related to the flow field inside the splicing chamber. This paper presents a numerical simulation of the flow char-acteristics inside the splicing chamber of the pneumatic splicer. A three-dimensional grid and the realizable tur¬bulence model are used in this simulation. The numerical results of veloc¬ity vectors distribution inside the chamber are shown. Streamlines starting from the two air injectors are also acquired. Based on the simulation, the principle of yarn splicing of the pneumatic splicer is discussed. The airflow in the splicing chamber can be divided into three regions. In addition, the simulation results have well sup¬ported the principle of yarn splicing of pneumatic splicer claimed by the splicing chamber makers.

Numerical Simulation and Stereo PIV Test of Inner Flow in a Double Blades Pump

2011 ◽  
Author(s):  
Kai Wang ◽  
Houlin Liu ◽  
Shouqi Yuan ◽  
Minggao Tan ◽  
Yong Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Velocity Field ◽  
Cfd Simulation ◽  
Research Work ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Absolute Velocity ◽  
Operation Condition ◽  
Test Technique ◽  
Simulation Results

A double blades pump is widely used in sewage treatment industry, while at present the research on the internal flow characteristics of the double blades pump is very few. So, the CFD technology and the stereo PIV test technique are applied to study the inner flow in a double blades pump whose specific speed is 110.9. The commercial code FLUENT is used to simulate the inner flow in the double blades pump at 0.6Qd, 0.8Qd, 1.0Qd, 1.2Qd and 1.4Qd. The RNG k-ε turbulence model and SIMPLEC algorithm are used in FLUENT. According to the results of the three-dimensional steady numerical simulation, the distributions of velocity field in the impeller are obtained at the five different operating conditions. The analysis of the numerical simulation results shows that there is an obvious vortex in the impeller passage at off-design conditions. But the number, location and area of the vortex are different from each operation condition. In order to validate CFD simulation results, the stereo PIV is used to test the absolute velocity distribution in the double blades pump at Jiangsu University. The distributions of three-dimensional absolute velocity field at the above five different operating conditions are obtained by the PIV test, and the measured results are compared with the CFD simulation results. The comparison indicates that there are vortexes in impeller passages of the double blades pump under the five operating conditions. But as to the area of the vortex and the relative velocity values of the vortex core, there are some differences between the experiment results and the numerical simulation results. The research work can be applied to instruct the hydraulic design of double blades pumps.

Numerical Simulation of the Nozzle with Self-Oscillating Flow Using the VOF Model

2012 ◽  
Vol 479-481 ◽  
pp. 2380-2382
Author(s):  
Zheng Fu Zhang ◽  
Jun Wei Wang ◽  
Feng Bao
Keyword(s):  
Numerical Simulation ◽  
Cfd Simulation ◽  
Immiscible Fluids ◽  
Oscillating Flow ◽  
Surface Tracking ◽  
Shape Models ◽  
Vof Model ◽  
Eulerian Mesh ◽  
Simulation Results ◽  
Fixed Period

The jet water shape of the nozzle will become a self-oscillating shape, if the triangle and U shape models are made into the normal nozzle. Using the VOF model , the jet shape of the nozzle will be simulated through a commercial CFD software 'FLUENT'. The VOF model (Volume of Fluid) is a surface-tracking technique applied to a fixed Eulerian mesh. It is designed for two or more immiscible fluids where the position of the interface between the fluids is of interest. The CFD simulation results shows that the jet shape of the nozzle is oscillate in a fixed period.

Accurate Determination of Critical Safety Height During Available Safe Egress Time Assessment

2016 ◽  
Vol 13 (10) ◽  
pp. 7545-7547
Author(s):  
Xuefeng Han ◽  
Yao Deng ◽  
Xiaomei Wang ◽  
Juncheng Jiang
Keyword(s):  
Numerical Simulation ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Accurate Determination ◽  
Hazard Index ◽  
Simulation Results ◽  
Time Assessment ◽  
Selection Of

When evaluating the ASET (available safe egress time), the fire scenario and the heat release rate (HRR) of the fire need to be set firstly according to the function and the combustible materials of the building, then CFD (Computational Fluent Dynamics) software is used to perform simulations. The ASET is obtained at the time when the hazard index of smoke reaches the minimum value at a safety height, and this height could be defined as critical safety height. It is very important to select critical safety height and heat release rate for the accuracy of the simulation results. The variation of selection of the critical safety height in references is large and it is lacking of credible evidence. This paper discusses the critical safety height based on statistics, probability and ergonomicsvvso as to improve the accuracy, credibility and reliability of the numerical simulation.

Droplet Generation and Piezoceramic Actuation of a Jetting Inker

2011 ◽  
Vol 480-481 ◽  
pp. 574-579
Author(s):  
Lue Zhang ◽  
Hong Hu ◽  
Yong Cao
Keyword(s):  
Numerical Simulation ◽  
Volume Of Fluid ◽  
Numerical Results ◽  
Droplet Generation ◽  
Phase Flow ◽  
Volume Of Fluid Method ◽  
Key Factors ◽  
Simulation Results

To reveal the jetting of fine drops, model of 2-phase flow between gas and liquid is offered based on volume of fluid method. Numerical simulation is launched for the droplet generation through narrow nozzle, and key factors are discussed. Aiming at the ink marking of defective dies in IC production, a jetting inker driven by piezoceramic stacks is developed. The actuation properties are derived; waveform of induced pressure at nozzle entrance is estimated, which coincides the numerical results. Performance of ink dot jetting is evaluated and simulation results are verified.

Research on Numerical Simulation of Quad Bundle Conductor on Galloping

2013 ◽  
Vol 457-458 ◽  
pp. 23-27
Author(s):  
Xue Ping Zhan ◽  
Kuan Jun Zhu ◽  
Cao Lan Liu ◽  
Bin Liu ◽  
Jun Zhang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Numerical Results ◽  
Kutta Method ◽  
Aerodynamic Parameter ◽  
Runge Kutta Method ◽  
Simulation Results ◽  
Runge Kutta ◽  
Element Method

The models of the multi-bundled conductors are constructed by finite element method in this paper. The numerical results are given by using the 4th order Runge-Kutta method considering aerodynamic parameter of sub-conductor. The simulation results are obtained on galloping of quad bundle conductors with the different span. Thus some effective numerical results of quad twin bundle conductor can provide a useful reference for anti-galloping design.

scholarly journals Numerical simulation of aerodynamic properties of separable elements of space-rocket systems in the LOGOS software package

2021 ◽  
Vol 2099 (1) ◽  
pp. 012072
Author(s):  
S V Aksenov ◽  
D A Korchazhkin ◽  
A Yu Puzan ◽  
O A Puzan
Keyword(s):  
Numerical Simulation ◽  
Computer Simulation ◽  
Software Package ◽  
Reference Data ◽  
Verification And Validation ◽  
Aerodynamic Properties ◽  
Space Rocket ◽  
Simulation Results

Abstract The work describes simulation results of the aerodynamic properties of split elements of the space-rocket systems in the LOGOS software package: the review of the advanced methods for aerodynamic properties has been carried out, the advantages of the computer simulation when solving such problems were demonstrated, verification and validation computations of the simulation problems for the split elements were performed, the produced results were compared with the reference data from available publications. The analysis of the results confirmed the applicability of the LOGOS software package for computing aerodynamic properties of the split elements.

The Influence of Turbulence Model Selection and Leakage Considerations on CFD Simulation Results for a Centrifugal Pump

2012 ◽  
Vol 594-597 ◽  
pp. 1940-1944
Author(s):  
Han Liu ◽  
Hua Chen Pan
Keyword(s):  
Numerical Simulation ◽  
Model Selection ◽  
Centrifugal Pump ◽  
Turbulence Model ◽  
Cfd Simulation ◽  
Turbulence Models ◽  
Leakage Flow ◽  
Pump Performance ◽  
Simulation Results

A commercial CFD software was used to simulate and predict a centrifugal pump performance. In this paper，the influences on the numerical simulation results using different turbulence models and different leakage flow assumptions were studied. The simulations are based on RANS with the and SST turbulence models. It is found that SST turbulence is better. Also the influence of the leakage flow was studied.

Numerical Study of the Dynamics of Particles Motion with Different Sizes from Coal-Based Thermal Power Plant

2019 ◽  
Vol 20 (2) ◽  
pp. 223-241 ◽  
Author(s):  
Alibek Issakhov ◽  
Ruslan Bulgakov ◽  
Yeldos Zhandaulet
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Mathematical Model ◽  
Power Plant ◽  
Thermal Power Plant ◽  
Thermal Power ◽  
Numerical Results ◽  
Simulation Results ◽  
Turbulent Models ◽  
The Mathematical Model

AbstractIn this paper, the propagation of particles with different sizes from a coal-based thermal power plant was investigated. It was found that the deterioration of the environment is due to the release of a large amount of SOx, NOx and the volatile particles of Suspended Particulate Matter and Respirable Suspended Particles matter, which cause human and animal diseases. This paper presents the numerical simulation results of air pollution by particles which having different sizes from thermal power plants in real sizes using a 3D model. For the adequacy of the mathematical model, a test problem was solved using different turbulent models. To assess the applicability of the mathematical model, the numerical algorithm and the choice of the optimal turbulent model, experimental data and numerical results of other authors were used. The obtained numerical simulation results are in good agreement with the experimental results and the numerical results of other authors. And to obtain more accurate numerical results for the experimental data for turbulent models ($k - \varepsilon $,$k - \omega $), there were certain corresponding boundary conditions for kinetic energy. Also, profiles of all flow characteristics were compared with and without particles and some effects of the particle on the flow were identified.

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