CFD Modeling and Validation of Steel Lazy-Wave Riser VIV

2016 ◽  
Author(s):  
Yiannis Constantinides ◽  
Maeanna Stover ◽  
Amanda Steele ◽  
Markku Santala
Keyword(s):  
Cfd Simulation ◽  
Cfd Modeling ◽  
Dynamic Stresses ◽  
Global Response ◽  
Computational Fluid Dynamics Cfd ◽  
Improved Performance ◽  
Cfd Method ◽  
Viv Suppression ◽  
Harsh Conditions ◽  
Good Agreement

The steel lazy wave riser is an emerging solution for deepwater applications in harsh conditions. The addition of buoyancy to provide the unique “lazy wave” shape reduces the dynamic stresses at the touchdown zone due to vessel motions and waves and results in improved performance. However, as the buoyant region cannot be easily fitted with VIV suppression, VIV becomes a critical aspect of the design. The present study progresses the modeling effort presented in [2] to model and understand the global response of a deepwater lazy wave riser using computational fluid dynamics (CFD). An industry first CFD simulation of a steel lazy wave riser under in-plane currents is presented and validated against experiments with two different configurations. Results show good agreement between CFD and experiments and provide an initial understanding of the riser response under in-plane currents. The CFD method developed has been validated and will be an important tool for the design of lazy wave risers.

VIV Assessment of Deepwater Lazy-Wave Risers

2014 ◽  
Author(s):  
Yiannis Constantinides ◽  
Michelle Zhang
Keyword(s):  
Cfd Simulation ◽  
Dynamic Stresses ◽  
Global Response ◽  
Software Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Improved Performance ◽  
Viv Suppression ◽  
Different Response ◽  
Semi Empirical ◽  
Harsh Conditions

The steel lazy wave riser is an emerging solution for deepwater applications in harsh conditions. The addition of buoyancy to provide the unique “lazy wave” shape reduces the dynamic stresses at the touchdown zone resulting in improved performance due to vessel motions and waves. However as the buoyant region cannot be easily fitted with Vortex-Induced Vibration (VIV) suppression, VIV becomes a critical aspect of the design. The present study focuses on understanding the global response of a deepwater lazy wave riser with a combination of computational fluid dynamics (CFD) and semi-empirical software analysis. An industry first full scale CFD simulation with different buoyancy region geometries is presented and analyzed to understand the field response and provide guidance on important aspects of design. Results show a different response than what was expected based on previous testing of similar systems, introducing a new parameter related to the aspect ratio of the buoyancy modules.

An anti-crystallization design of selective catalytic reduction nozzle holder

2021 ◽  
pp. 095440702097084
Author(s):  
Dewen Liu ◽  
Kai Lu ◽  
Shusen Liu ◽  
Yan Wu ◽  
Shuzhan Bai
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Injection System ◽  
Test Results ◽  
Verification Methods ◽  
Crystallization Risk ◽  
Protective Cover ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Good Agreement

From the aspect of reducing the risk of crystallization on nozzle surface, a new design of nozzle protective cover was to solve the problem in selective catalytic reduction (SCR) urea injection system. The simulation calculation and experimental verification methods were used to compare different schemes. The results show that reducing the height of nozzle holder can reduce the vortex currents near nozzle surface and effectively reduce the risk of crystallization on the nozzle surface. It is proposed to install a protective cover in the nozzle holder under the scheme of reducing the height of nozzle holder, which can further eliminate the vortex. Simulation and test results demonstrate good agreement under the rated running condition. The scheme of adding a protective cover in the nozzle holder shows the least crystallization risk by computational fluid dynamics (CFD) method. The crystallization cycle test shows that, after the height of nozzle holder is reduced, the risk of crystallization on the nozzle surface is reduced correspondingly. The addition of a protective cover in the nozzle holder solves the problem of crystallization on the nozzle surface, which provides a new method for anti-crystallization design.

scholarly journals Biomagnetic Monitoring vs. CFD Modeling: A Real Case Study of Near-Source Depositions of Traffic-Related Particulate Matter along a Motorway

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1285
Author(s):  
Sarah Letaïef ◽  
Pierre Camps ◽  
Thierry Poidras ◽  
Patrick Nicol ◽  
Delphine Bosch ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particulate Matter ◽  
Cfd Simulation ◽  
Low Cost ◽  
Precast Concrete ◽  
Cfd Modeling ◽  
Concrete Wall ◽  
Fluorescence Measurements ◽  
Computational Fluid Dynamics Cfd

A test site located along a 12-lane motorway east of Montpellier, France, is used to evaluate the potential of biomagnetic monitoring on traffic-related particulate matter (PM) to parametrize a computational fluid dynamics (CFD) simulation of the local airflow. Two configurations were established on the site with three vegetated flat-top earth berms of a basic design, and a fourth one was located windward to the traffic roofed with a 4-m-high precast concrete wall. As a first step, PM deposition simultaneously on plant leaves, on low-cost passive artificial filters, and on soils was estimated from proxies supplied by magnetic and X-ray fluorescence measurements on both sides of the motorway. These latter revealed that traffic-related pollutants are present on soils samples highlighted with a clear fingerprint of combustion residues, and wears of breaks, vehicles, and highway equipment. Maximum PM accumulations were detected in the lee of the berm–wall combination, while no significant deposition was observed on both sides of the flat-top earth berms. These results are in line with measurements from PM µ-sensors operated by the regional state-approved air quality agency. Finally, we compared the experimental measurements with the outcomes of a computational fluid dynamics (CFD) modeling based on the Reynolds-Averaged Navier–Stokes (RANS) equations that consider the traffic-induced momentum and turbulence. The CFD modeling matches the experimental results by predicting a recirculated flow in the near wake of the berm–wall combination that enhances the PM concentration, whereas the flat-top berm geometry does not alter the pollutants’ transport and indeed contributes to their atmospheric dispersion.

scholarly journals ICCM2015: A Comparison of RANS and LES Computational Methods in Analyzing Ventilation Flow Through a Room Fitted with a Two-Sided Windcatcher

2017 ◽  
Vol 14 (03) ◽  
pp. 1750021 ◽  
Author(s):  
A. Niktash ◽  
B. P. Huynh
Keyword(s):  
Natural Ventilation ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Interior Space ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
Cfd Method ◽  
Good Agreement

A windcatcher is a structure for providing natural ventilation using wind power; it is usually fitted on the roof of a building to exhaust the inside stale air to the outside and supplies the outside fresh air into the building interior space working by pressure difference between outside and inside of the building. In this paper, the behavior of free wind flow through a three-dimensional room fitted with a centered position two-canal bottom shape windcatcher model is investigated numerically, using a commercial computational fluid dynamics (CFD) software package and LES (Large Eddy Simulation) CFD method. The results have been compared with the obtained results for the same model but using RANS (Reynolds Averaged Navier–Stokes) CFD method. The model with its surrounded space has been considered in both method. It is found that the achieved results for the model from LES method are in good agreement with RANS method’s results for the same model.

scholarly journals Characterization of an aerodynamic lens for transmitting particles greater than 1 micrometer in diameter into the Aerodyne aerosol mass spectrometer

2013 ◽  
Vol 6 (11) ◽  
pp. 3271-3280 ◽  
Author(s):  
L. R. Williams ◽  
L. A. Gonzalez ◽  
J. Peck ◽  
D. Trimborn ◽  
J. McInnis ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Transmission Efficiency ◽  
Cfd Modeling ◽  
Operating Pressure ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Valve Assembly ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

Abstract. We have designed and characterized a new inlet and aerodynamic lens for the Aerodyne aerosol mass spectrometer (AMS) that transmits particles between 80 nm and more than 3 μm in vacuum aerodynamic diameter. The design of the inlet and lens was optimized with computational fluid dynamics (CFD) modeling of particle trajectories. Major changes include a redesigned critical orifice holder and valve assembly, addition of a relaxation chamber behind the critical orifice, and a higher lens operating pressure. The transmission efficiency of the new inlet and lens was characterized experimentally with size-selected particles. Experimental measurements are in good agreement with the calculated transmission efficiency.

A New 1.5-Stage Turbine Wheelspace Hot Gas Ingestion Rig (HGIR): Part II — CFD Modeling and Validation

2013 ◽  
Author(s):  
Zhongman Ding ◽  
Pepe Palafox ◽  
Kenneth Moore ◽  
Raymond Chupp ◽  
Kevin Kirtley
Keyword(s):  
Test Data ◽  
Cfd Simulation ◽  
Operating Conditions ◽  
Cfd Modeling ◽  
Test Configuration ◽  
Reduced Order ◽  
Sector Model ◽  
Hot Gas ◽  
Seal Design ◽  
Good Agreement

Fundamental test data for different rim seal geometries have been obtained from the Hot Gas Ingestion Rig (HGIR), a scaled 1.5-stage turbine rig configured from a current generation heavy duty gas turbine. With well-controlled operating conditions the rig has provided valuable sets of data for CFD tool validation. Part I of this work [1] introduced details on the HGIR design and test data summary from selected rim seal configurations and test conditions. In this study, Part II, CFD simulations were carried out on the baseline test configuration, and different modeling approaches were compared to identify and validate a “reduced-order” CFD methodology, i.e. CFX analyses using the k-ε model with scalable wall function. The results show steady state CFD simulation to be incapable of predicting the ingestion levels observed from rig data. However, unsteady solutions using a two-vane/four-blade sector model including a stator-rotor domain interface showed ingestion over the outer rim seal that was in reasonably good agreement with test data. Good agreement was also obtained on pressure distributions in the circumferential direction. The identified “reduced-order” CFD modeling methodology demonstrated enough sensitivity to differentiate between sealing geometry variations, and thus can be applied to guide rim seal design.

Simulation of Circular Tubes Fitted with V Cut and Square Cut Rotors

2013 ◽  
Vol 561 ◽  
pp. 547-552
Author(s):  
Peng Jiang ◽  
Hua Yan ◽  
Zhen Zhang ◽  
Yu Mei Ding ◽  
Wei Min Yang
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Turbulent Heat Transfer ◽  
Cfd Modeling ◽  
Turbulent Heat ◽  
Circular Tubes ◽  
Performance Factor ◽  
Thermal Performance Factor ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

This work presents the effect of V cut and square cut rotors in circular tubes for turbulent heat transfer using computational fluid dynamics (CFD) modeling. The computational results are in good agreement with experimental data. The obtained results reveal that the use of square cut rotors leads to higher Nusselt number than use of V cut rotors. The results also show that the heat transfer rate, friction factor and thermal performance factor of rotors with square cut increase with the increase of width (a) and depth (b) of rotors’ cut. Square cut rotors with a=b=3 yields higher mean thermal performance factor than those with other width and depth, a=b=1, 2 and the highest thermal performance factor of square cut rotors at a=b=1, 2, 3 are found to be 2.08, 2.11 and 2.13.

Experimental and theoretical analyses of two-dimensional flows upstream of broad-crested weirs

2008 ◽  
Vol 35 (9) ◽  
pp. 975-986 ◽  
Author(s):  
M. Salih Kirkgoz ◽  
M. Sami Akoz ◽  
A. Alper Oner
Keyword(s):  
Cfd Simulation ◽  
Turbulence Models ◽  
Free Surface Flows ◽  
Velocity Fields ◽  
Numerical Results ◽  
Cfd Modeling ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Image Velocimetry ◽  
Computational Fluid Dynamics Cfd

Using the particle image velocimetry (PIV) technique, the laboratory experiments are conducted to measure the velocity fields of two-dimensional turbulent free surface flows upstream of rectangular and triangular broad-crested weirs. The experimental flow cases are analyzed theoretically by a computational fluid dynamics (CFD) modeling in which the finite element method is used to solve the governing equations. In the CFD simulation, the volume of fluid (VOF) method is used to compute the free surfaces of the flows. Using the standard k–ε and standard k–ω turbulence models, the numerical results for the velocity fields and flow profiles are compared with the experimental results for validation purposes. The computed results using k–ω turbulence model on compressed mesh systems are found in good agreement with measured data. The flow cases are also analyzed theoretically using the potential flow (PF) approach, and the numerical results for the velocity fields are compared with measurements.

scholarly journals Performance Investigation of The Bed Adsorption of An Adsorption Desalination Using CFD Simulation

2021 ◽  
Author(s):  
Mohamad Hossein Bakhshandeh ◽  
Taleb Zarei ◽  
Jamshid Khorshidi
Keyword(s):  
Silica Gel ◽  
Water Uptake ◽  
Cfd Simulation ◽  
Finned Tube ◽  
Copper Plate ◽  
Cfd Modeling ◽  
Desorption Process ◽  
Critical Elements ◽  
Computational Fluid Dynamics Cfd ◽  
Fin Thickness

Abstract One of the critical elements of an adsorption desalination system is the adsorption bed. System dynamics of a 2-bed single-stage silica gel plus water-based AD system was analyzed. A great pattern is expanded using energy conservation and mass connected with the kinetics of the ad- sorption/desorption process. Computational fluid dynamics (CFD) modeling was handled for simulation of the adsorption process for a rectangular finned tube-based adsorption bed featured with silica gel adsorbent substance. For the simulation, the adsorbents were considered as a solid volume with defined porosity based on Darcy equation. The adsorption and desorption mode of the adsorption bed was simulated. The CFD techniques were then applied to study fin thickness and fin height. The results showed that decreasing the fin thickness increased the water uptake by up to 8% and decreased the fin height from 30mm to 20mm, which resulted in an increase of the water uptake up to 17%. The CFD technique was also used to investigate the effect of plate type on the adsorption bed performance. The results showed that the copper plate improved the water uptake up to 9%. The copper plate decreased the temperature of the adsorption bed up to 11% more than the aluminum plate.

scholarly journals Vortex Dynamics Analysis of Straight-Body-Type-Fuselage Fighter Using CFD Simulation

2020 ◽  
Author(s):  
Sutrisno Sutrisno ◽  
Deendarlianto Deendarlianto ◽  
Tri Agung Rohmat ◽  
Setyawan Bekti Wibowo ◽  
Sigit Iswahyudi
Keyword(s):  
Performance Improvement ◽  
Cfd Simulation ◽  
Vortex Generation ◽  
Vortex Dynamic ◽  
Body Type ◽  
Surface Pressure Distribution ◽  
Negative Surface ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Velocity Pressure

The choice for using a fighter fuselage in a fighter jet design affects a vortex generation advantageous in maneuverability. To study the effect of straight-body-type-fuselage (SBTF) on the vortex dynamic, a computational fluid dynamics (CFD) method is used, in order to simulate a model of SBTF fighter. The simulation uses Q-criterion to probe vortices, and a logarithmic grid to emphasize the micro-gridding effect of the turbulent boundary layer. The results show detailed quantitative velocity, pressure, trajectory of the vortex core, and wing negative surface pressure distribution (SPD), providing clear pictures of opportunity for performance improvement, better lift, agility, and maneuverability of a fighter if a model requires a new design.

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