CFD Analysis of the BeVERLI Hill Turbulence Model Validation Experiments

2022 ◽  
Author(s):  
Thomas A. Ozoroski ◽  
Aldo Gargiulo ◽  
Julie E. Duetsch-Patel ◽  
Vignesh Sundarraj ◽  
Christopher J. Roy ◽  
...  
Keyword(s):  
Model Validation ◽  
Turbulence Model ◽  
Cfd Analysis ◽  
Validation Experiments

Examination of Flow Sensitivities in Turbulence Model Validation Experiments

2020 ◽  
Author(s):  
Aldo Gargiulo ◽  
Colton Beardsley ◽  
Vidya Vishwanathan ◽  
Daniel J. Fritsch ◽  
Julie E. Duetsch-Patel ◽  
...  
Keyword(s):  
Model Validation ◽  
Turbulence Model ◽  
Validation Experiments

Analysis of an Airfoil Using a Transition and Turbulence Model

2016 ◽  
Vol 819 ◽  
pp. 356-360
Author(s):  
Mazharul Islam ◽  
Jiří Fürst ◽  
David Wood ◽  
Farid Nasir Ani
Keyword(s):  
Fluid Dynamics ◽  
Boundary Layer ◽  
Computational Fluid Dynamics ◽  
Kinetic Energy ◽  
Turbulence Model ◽  
Original Version ◽  
Transitional Region ◽  
Cfd Analysis ◽  
Computational Fluid Dynamics Cfd

In order to evaluate the performance of airfoils with computational fluid dynamics (CFD) tools, modelling of transitional region in the boundary layer is very critical. Currently, there are several classes of transition-based turbulence model which are based on different methods. Among these, the k-kL- ω, which is a three equation turbulence model, is one of the prominent ones which is based on the concept of laminar kinetic energy. This model is phenomenological and has several advantageous features. Over the years, different researchers have attempted to modify the original version which was proposed by Walter and Cokljat in 2008 to enrich the modelling capability. In this article, a modified form of k-kL-ω transitional turbulence model has been used with the help of OpenFOAM for an investigative CFD analysis of a NACA 4-digit airfoil at range of angles of attack.

scholarly journals THERMODYNAMIC ANALYSIS OF WIND CATCHER WITH COOLING PADS USING SSG REYNOLDS STRESS TURBULENCE MODEL.

2021 ◽  
Author(s):  
Agarwal A ◽  
◽  
Pitso I ◽  
Letsatsi M.T ◽  
◽  
...  
Keyword(s):  
Reynolds Stress ◽  
Turbulence Model ◽  
Energy Requirement ◽  
Renewable Energy Sources ◽  
Thermal Conditions ◽  
Energy Sources ◽  
Cfd Analysis ◽  
Open Design ◽  
Air Inlet ◽  
Environment Sustainability

With increase in energy requirement, the researchers are looking for energy efficient passive ventilation techniques. The current design concept is based on environment sustainability and use of renewable energy sources is preferred over conventional energy sources. The current research investigates the wind catcher design with cooling pads using techniques of Computational Fluid Dynamics. The CAD model of wind catcher is designed using Creo design software and CFD analysis is conducted using ANSYS CFX software. The CFD analysis is directed at different air inlet velocities and SSG Reynolds stress turbulence model under steady state thermal conditions for both side open design and singe side open designs. The cooling pads have successfully reduced temperature up to 1.65 degrees for single side opening and 2.86 degrees for double side opening design. Maximum air flow rate is achieved with higher air inlet velocities for both design types.

Vapor cloud explosions in various types of confined environments: CFD analysis and model validation

2021 ◽  
pp. 104681
Author(s):  
G. Momferatos ◽  
S.G. Giannissi ◽  
I.C. Tolias ◽  
A.G. Venetsanos ◽  
A. Vlyssides ◽  
...  
Keyword(s):  
Model Validation ◽  
Cfd Analysis ◽  
Vapor Cloud

Numerical Simulation of Unsteady Flow in a Submersible Axial Flow Pump

2013 ◽  
Vol 444-445 ◽  
pp. 486-489
Author(s):  
Xiao Xu Zhang ◽  
Hong Ming Zhang ◽  
Xiao Ping Li
Keyword(s):  
Numerical Simulation ◽  
Unsteady Flow ◽  
Turbulence Model ◽  
Axial Flow ◽  
Simple Algorithm ◽  
Flow Rule ◽  
Cfd Analysis ◽  
Flow Passage ◽  
Axial Flow Pump ◽  
Flow Pump

To make the submersible axial flow pump have better performance, it is very significant to know about the flowing distributions. Based on N-S equations and Standard turbulence model and SIMPLE algorithm, a CFD analysis was made of the full flow passage in this type of pump. The study result shows the flow rule and will provide a guide for the designing and the producing practice.

scholarly journals CFD Analysis of a SD 7003 Airfoil with a Local Correlation Based Transition and Turbulence Model

2017 ◽  
Vol 184 ◽  
pp. 012067
Author(s):  
Mazharul Islam ◽  
Felix Langfeldt ◽  
Jiří Fürst ◽  
David H Wood
Keyword(s):  
Turbulence Model ◽  
Cfd Analysis ◽  
Local Correlation

Development of an Analysis Methodology for Pressure Flow Scour Under Flooded Bridge Decks Using Commercial CFD Software

2010 ◽  
Author(s):  
Dipankar Biswas ◽  
Steven A. Lottes ◽  
Pradip Majumdar ◽  
Milivoje Kostic
Keyword(s):  
Shear Stress ◽  
Turbulence Model ◽  
Critical Shear Stress ◽  
Scour Depth ◽  
Bed Shear Stress ◽  
Cfd Analysis ◽  
Flow Conditions ◽  
Pressure Flow ◽  
Scour Hole ◽  
Bridge Failure

Bridges are a significant component of the ground transportation infrastructure in the United States. With about sixty percent of bridge failures due to hydraulic causes, primarily scour, application of computational fluid dynamics (CFD) analysis techniques to the assessment of risk of bridge failure under flood conditions can provide increased accuracy in scour risk assessment at a relatively low cost. The analysis can be used to make optimum use of limited federal and state funds available to maintain and replace bridges and ensure public safety while traveling on the nation’s roads and highways during and after floods. Scour is the erosion of riverbed material during high flow conditions, such as floods. When scouring of the supporting soil around the piers and abutments of bridges takes place, risk of bridge failure increases. A simulation methodology to conservatively predict equilibrium shape and size of the scour hole under pressure flow conditions for flooded bridge decks using commercial CFD software was developed. The computational methodology has been developed using C++ to compute changes in the bed contour outside of the CFD software and generate a re-meshing script to change the bed boundary contour. STAR-CD was used to run the hydrodynamic analysis to obtain bed shear stress, and a BASH script was developed to automate cycling between computing bed shear stress with the CFD software and computing changes in the bed contour due to scour predicted using the computed shear stress for the current bed contour. A single-phase moving boundary formulation has been developed to compute the equilibrium scour hole contour that proceeds through a series of quasi-steady CFD computations. It is based on CFD analysis of the flow fields around the flooded bridge deck and shear stress computed at the bed modeled as a rough wall. A high Reynolds number k-ε turbulence model with standard wall functions, based on a Reynolds-Averaged Navier-Stokes (RANS) turbulence model, was used to compute bed shear stress. The scour sites on the bed were identified as those sites where the computed shear stress exceeded the critical shear stress computed from a published correlation for flat bed conditions. Comparison with experimental data obtained from the Turner-Fairbank Highway Research Center (TFHRC), McLean, VA, USA, revealed larger discrepancies than anticipated between the bridge inundation ratio and the scour hole depth. Although scour hole slopes were small for the cases tested, a correction to critical shear stress to account for bed slope was also tested. It did not significantly improve the correlation between CFD prediction and experimental observations. These results may be a consequence of using only excess shear stress above critical as a criteria for scour when other physical mechanisms also contribute to the initiation of scour. Prediction of scour depth using federal guidelines over predicts scour depth by as much as an order of magnitude in some cases. Over prediction is acceptable for purposes of ensuring bridge safety. CFD methods for scour prediction can be a significant improvement of current methods as long as under prediction of scour depth is avoided. Conservative scour prediction using CFD methods can be achieved by using conservative values of parameters such as critical shear stress and effective bed roughness.

scholarly journals Improving the methodology for calculation of energy losses in axial turbine cascades

2021 ◽  
pp. 104-109
Author(s):  
М.Ю. Левенталь ◽  
Ю.М. Погодин ◽  
Ю.Р. Миронов
Keyword(s):  
Standard Deviation ◽  
Turbulence Model ◽  
Empirical Model ◽  
Turbulence Models ◽  
Operating Parameters ◽  
Cfd Analysis ◽  
Sample Standard Deviation ◽  
Rans Model ◽  
Wide Range ◽  
Turbine Cascades

Представлена оценка неопределенности прогнозирования потерь энергии в решетках профилей осевых турбин. В сравнении с экспериментальными данными рассмотрены эмпирическая модель ЦИАМ и метод CFD анализа в рамках RANS модели. Геометрические и режимные параметры решеток профилей варьируются в широком диапазоне. Результаты CFD расчета отличаются существенно в зависимости от модели турбулентности. Наименьшая неопределенность получена для модели рейнольдсовых напряжений RSM. Определено выборочное стандартное относительное отклонение для анализируемой базы данных. Применительно к CFD расчету данное отклонение составило 18,6%, применительно к эмпирической модели ЦИАМ 46,4%. Разработана эмпирическая модель коррекции потерь полученных по результатам CFD анализа с моделью турбулентности RSM. Корректирующая функция включает в себя геометрические и режимные параметры решеток и особенности течения в межлопаточном канале (всего 14 параметров). Использование разработанного подхода позволило снизить неопределённость прогнозирования потерь в 2 раза. В результате работы выборочное стандартное относительное отклонение предсказания потерь для рассматриваемой базы решеток профилей составило 9,3%. Estimation of the uncertainty in predicting profile losses using various models was performed. In comparison with the experimental data, empirical model of CIAM and method of CFD analysis are considered. RANS models are used. The geometric and operating parameters of the analyzed turbine cascades vary over a wide range. Turbulence models strongly influence loss prediction uncertainty. The smallest uncertainty was obtained using the RSM turbulence model. The sample standard deviation for the considered turbine cascades base was determined. The deviation for CFD analysis is 18.6%. For the empirical model of CIAM the deviation is 46.4%. The new empirical model has been created to correct the results of calculating losses according to the RANS model using the RSM turbulence model. The corrective function takes into account the influence of the geometric and operating parameters of the turbine cascades and the features of the airfoil flow (14 parameters in total). The developed approach allows reducing the uncertainty in the estimation of losses according to the RANS model by 2 times. As a result, the sample standard deviation in the prediction of losses is 9.3% for the considered turbine cascades base.

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