CFD Virtual Testing for Resistance, Wind and Current Loads on a Supply Boat

2012 ◽  
Author(s):  
Daniel Fonseca de Carvalho e Silva
Keyword(s):  
Numerical Approach ◽  
Interfacial Effects ◽  
Environmental Loads ◽  
Towing Tank ◽  
Cfd Models ◽  
Fluid Resistance ◽  
Ansys Cfx ◽  
Mesh Density ◽  
Simulation Results ◽  
Icem Cfd

Ship and platforms environmental loads are often predicted by model scale experiments or empirical calculations only. This paper presents the application of a commercial CFD (Computational Fluid Dynamics) software as a numerical approach to calculate the flow around a supply boat considering current, wind loads and fluid resistance determination. Since, owing to many practical situations, free surface effects can be neglected, the above and underwater problems can be uncoupled and independently evaluated, although for higher Froude number cases in the resistance determination the interfacial effects have to be considered. Throughout this paper, the assumptions adopted and the boundary conditions applied are discussed. All meshes were developed on ICEM CFD® and appropriate mesh density studies indicate that meshes with approximately 2 million nodes can represent the experiments accurately. The simulations were conducted using the ANSYS CFX® solver, using Perl scripting for automatic evaluation of multiple run settings and simulation execution at Petrobras Research Center Clusters. The results for each case are compared with either towing tank or wind tunnel experimental data, both harvested at IPT (Instituto de Pesquisas Tecnológicas). The comparison between simulation results and experiments allows the analysis of the present CFD models benefits and limitations, providing guidelines for future similar studies. The overall match between laboratory and virtual tests results supports the expansion of this procedure to other vessels and offshore floating units.

Effects on Drillship Resistance of a Large Moonpool Using CFD Simulations With Experimental Validation

2016 ◽  
Author(s):  
Lucas do Vale Machado ◽  
Antonio Carlos Fernandes ◽  
Anis Altaf Hussain
Keyword(s):  
Oil And Gas ◽  
Numerical Study ◽  
Experimental Tests ◽  
Numerical Approach ◽  
Process Efficiency ◽  
Floating Structure ◽  
Cfd Models ◽  
Waves And Currents ◽  
Mesh Density ◽  
In Transit

Drillship is a marine vessel designed for drilling purposes of oil and gas wells. This kind of vessel has what is called a moonpool that is an opening on the base of the hull used for drilling operation. Nowadays, in search of better process efficiency, some of these drillships are being constructed with dual-derrick and are in need of a larger moonpool, which results in some effects on the floating structure, such as resistance increase. The main objective of this paper is to investigate the influence of shape and size of the moonpool on the resistance of a drillship dual derrick, while in transit. It presents the application of a commercial CFD (Computational Fluid Dynamics) software as a numerical approach to calculate the flow around a drillship without neglecting free surface effects. Throughout this work, the made assumptions, applied boundary conditions and appropriate mesh density studies are thoroughly discussed. Verification assessment is part of the work. In addition to the numerical study, some experimental tests were done at LOC/UFRJ (Laboratório de Ondas e Correntes – Laboratory of Waves and Currents) to validate the numerical approach. The comparison between simulation results and experiments allows the analysis of the present CFD models benefits and limitations, providing guidelines for similar future studies. The overall match between laboratory and virtual tests results supports the expansion of this procedure to other vessels and offshore floating units. The results of this work clarify the motion inside the moonpool and its effects. Furthermore, it gives the results of several different moonpool profiles that were optimized for this specific hull.

scholarly journals Modelling of working processes of non-contact oil free vacuum pumps by computational fluid dynamics (CFD) methods

2021 ◽  
Vol 2059 (1) ◽  
pp. 012003
Author(s):  
A Burmistrov ◽  
A Raykov ◽  
S Salikeev ◽  
E Kapustin
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Mathematical Models ◽  
Cfd Models ◽  
Ansys Cfx ◽  
Sst Turbulence Model ◽  
Computational Fluid Dynamics Cfd ◽  
Dynamic Meshing ◽  
Comparison With Experimental Data

Abstract Numerical mathematical models of non-contact oil free scroll, Roots and screw vacuum pumps are developed. Modelling was carried out with the help of software CFD ANSYS-CFX and program TwinMesh for dynamic meshing. Pumping characteristics of non-contact pumps in viscous flow with the help of SST-turbulence model were calculated for varying rotors profiles, clearances, and rotating speeds. Comparison with experimental data verified adequacy of developed CFD models.

scholarly journals Numerical Investigation of a Hydropower Tunnel: Estimating Localised Head-Loss Using the Manning Equation

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1562 ◽  
Author(s):  
L. Robin Andersson ◽  
J. Gunnar I. Hellström ◽  
Patrik Andreasson ◽  
T. Staffan Lundström
Keyword(s):  
Head Loss ◽  
Water Tunnel ◽  
Hydraulic Radius ◽  
Dominant Effect ◽  
Cross Sectional ◽  
Ansys Cfx ◽  
Roughness Elements ◽  
Future Evaluation ◽  
Sectional Shape ◽  
Icem Cfd

The fluid dynamics within a water tunnel is investigated numerically using a RANS approach with the k- ε turbulence model. The computational model is based on a laser scan of a hydropower tunnel located in Gävunda, Sweden. The tunnel has a typical height of 6.9 m and a width of 7.2 m. While the average cross-sectional shape of the tunnel is smooth the local deviations are significant, where some roughness elements may be in the size of 5 m implying a large variation of the hydraulic radius. The results indicate that the Manning equation can successfully be used to study the localised pressure variations by taking into account the varying hydraulic radius and cross-sectional area of the tunnel. This indicates a dominant effect of the tunnel roughness in connection with the flow, which has the potential to be used in the future evaluation of tunnel durability. ANSYS-CFX was used for the simulations along with ICEM-CFD for building the mesh.

Numerical Simulation of Broadband Combustion Noise With the RPM-CN Approach

2009 ◽  
Author(s):  
B. Mu¨hlbauer ◽  
R. Ewert ◽  
O. Kornow ◽  
B. Noll ◽  
M. Aigner
Keyword(s):  
High Efficiency ◽  
Numerical Approach ◽  
Combustion Noise ◽  
Acoustic Measurements ◽  
Noise Sources ◽  
Computational Costs ◽  
Acoustic Perturbation ◽  
Simulation Results ◽  
The Time Domain ◽  
Good Agreement

A new numerical approach called RPM-CN approach is applied to predict broadband combustion noise. This highly efficient hybrid CFD/CAA approach can rely on a reactive RANS simulation. The RPM method is used to reconstruct stochastic broadband combustion noise sources in the time domain based on statistical turbulence quantities. Subsequently, the propagation of the combustion noise is computed by solving the acoustic perturbation equations (APE-4). The accuracy of the RPM-CN approach will be demonstrated by a good agreement of the simulation results with acoustic measurements of the DLR-A flame. The high efficiency and therefore low computational costs enable the usage of this numerical approach in the design process.

Influence of Mesh Density and Turbulence Models on 2D Viscous Flutter in 11th Standard Configuration

2012 ◽  
Author(s):  
Aleksandra Pajak ◽  
Romuald Rzadkowski
Keyword(s):  
Large Deviations ◽  
Numerical Simulations ◽  
Qualitative Agreement ◽  
Phase Distribution ◽  
Turbulence Models ◽  
Experimental Results ◽  
Pressure Amplitude ◽  
Ansys Cfx ◽  
Mesh Density ◽  
Standard Configuration

In this study, numerical simulations of 2D viscous flutter were performed and compared with the available experimental results for different mesh density and different turbulence models. The calculations were carried out for bending oscillations of the cascade known as the Eleventh Standard Configuration. The ANSYS CFX v.12.1 code with SST, SA, k-ω turbulence models was used for calculations with various values of the inter-blade phase angle. Three moving H-O grids were used. Comparison of the calculated and the experimental results for the Eleventh Standard Configurations for the IBPA = 180 deg has shown good quantitative and qualitative agreement for local performances (unsteady pressure amplitude and phase distribution). For the IBPA = 90 and −90 deg the results are correct only in terms of amplitude. The phase distribution showed large deviations. The effect of various grids as well as SST, Spalart Allmaras and k-ω turbulence models was not significant in the subsonic case, but it turned out to be very noticeable in the transonic case.

Numerical and Analytical Modeling of Laser Deposition With Preheating

2007 ◽  
Author(s):  
Zhiqiang Fan ◽  
Jacquelyn K. Stroble ◽  
Jianzhong Ruan ◽  
Todd E. Sparks ◽  
Frank Liou
Keyword(s):  
Analytical Modeling ◽  
Deposition Process ◽  
Numerical Approach ◽  
Laser Deposition ◽  
Surface Evolution ◽  
Melt Pool ◽  
Solid Models ◽  
Simulation Results ◽  
Analytical Approaches ◽  
Material Interaction

Laser deposition allows quick fabrication of fully-dense metallic components directly from CAD solid models. This work uses both numerical and analytical approaches to model the laser deposition process including actual deposition and preheating. The numerical approach is used to simulate the coupled, interactive transport phenomena during actual deposition. The numerical simulation involves laser material interaction, free surface evolution, and melt-pool dynamics. The analytical approach is used to model heat transfer during preheating. The combination of these two approaches can increase computational efficiency with most of the phenomena associated with laser deposition modeled. The simulation is applied to Ti-6Al-4V and simulation results are compared with experimental results.

scholarly journals Gaya Hambat Saat Hidro Planing dan Gaya Angkat Aerodinamika Saat Cruise di Efek Permukaan pada Pesawat Wing in Surface Effect

WARTA ARDHIA ◽  
2017 ◽  
Vol 42 (2) ◽  
pp. 71
Author(s):  
Sayuti Syamsuar
Keyword(s):  
Surface Effect ◽  
Delta Wing ◽  
The Body ◽  
Test Model ◽  
Towing Tank ◽  
Ansys Cfx ◽  
Effect Theory ◽  
Towing Tank Test ◽  
Hydrodynamic Wave ◽  
Aerodynamic Lift

Perhitungan komputasional dinamika fluida pada model 3 Dimensi pada pesawat Wung In Surface Effect sangat penting untuk mengetahui data hasil uji towing tank dan uji terbang. Konfigurasi Lippisch mempunyai sayap berbentuk inverse delta dan punuk di atasnya menggunakan airfoil jenis Clark Y yang telah dirancang untuk memenuhi karakteristik efek permukaan. Piranti lunak pertama Maxsurf digunakan untuk membandingkan hasil uji model towing tank saat fase hydro planing. Piranti lunak kedua ANSYS CFX digunakan untuk menghitung gaya hambat air dan gaya angkat aerodinamika dari pesawat Wing In Surface Effect kapasitas 8 orang model 3 Dimensi dengan konfigurasi Berat Maksimum saat take off sebesar 32000 Newton pada kecepatan cruise 80 knots pada ketinggian terbang 2.5 meter. Aspek eksperimen pada uji model towing tank dan data uji terbang pada prototipe pesawat Wing In Surface Effect kapasitas (1-2) orang saat hydro planing dijelaskan dengan menggunakan teori gelombang hidrodinamika dan porpoising efek. [The Hump Drags During Hydro planing and Aerodynamic Lift During Cruise in Surface Effect Altitude Of Wing in Surface Effect Craft] The computational fluid dynamics of 3 Dimensions model of Wing in Surface Effect craft is very important to proof the model towing test and flight testing data. The inverse delta wing and shoulder airfoil is by using Clark Y of Lippisch configurations have been designed for the surface effect characteristics. The first Maxsurf software are used to compared the towing test results during hydro planing phase. The second ANSYS CFX software is used to calculate the hump drags and aerodynamic lift of Wing In Surface Effect craft 8 seaters 3 Dimensions model to verified the Design Requirement and Objectives. The forces equilibrium on the body axis during hydro planing are very important to fulfill the take off phase on the water surface. And, the aerodynamic lift for Maximum Take off Weight of 8 seaters configuration is 32000 Newton during cruise speed at 80 knots on the 2.5 meter altitude. The experimental aspects of towing tank test model and Wing In Surface Effect craft (1-2) seaters prototype during hydro planing test have been proposed by using the hydrodynamic wave and porpoising effect theory.

Finite Element Modeling and Simulation of Thermal Distribution on Full and Ventilated Electric Vehicle Disk Brake

2014 ◽  
Vol 699 ◽  
pp. 372-377
Author(s):  
Eko Prasetya Budiana ◽  
Ubaidillah ◽  
Hafidz Adyatama ◽  
Dominicus Danardono Dwi Prija
Keyword(s):  
Mechanical Energy ◽  
Heat Distribution ◽  
Brake Disk ◽  
Disk Brake ◽  
Thermal Distribution ◽  
Vehicle Load ◽  
Ansys Cfx ◽  
Simulation Results ◽  
Braking Process ◽  
Full Disk

This paper examines the phenomenon of heat distribution on the disk while braking. Heat distribution on the brake disk is caused by the change of the kinetic energy into the mechanical energy. The energy change occurs during the process of braking due to the friction between the surfaces of the disk with the caliper pad. Friction also results in the increase of temperature, This phenomenon is very important to be highlighted in order to learn the characteristic of heat distribution occurs on the disk with different disk types namely ventilation disk and full disk. In addition, this study is also aimed to find out the effect of vehicle load on disk temperature during braking process. The purpose of this research is to analyze the thermal distribution of a vehicle disk brake. The thermal distribution on the disk brake is investigated using ANSYS CFX. This simulation results provide useful information for identifying the influence of different models of disks brake as well as the vehicle load with regard to the distribution of heat that occurs during the process of braking.

Surface Piercing Drag in CFD

2011 ◽  
Author(s):  
Will Bowen ◽  
Keith Alexander
Keyword(s):  
Atmospheric Pressure ◽  
Experimental Results ◽  
Back Side ◽  
Flat Plates ◽  
Two Phase ◽  
Towing Tank ◽  
Flow Energy ◽  
Ansys Cfx ◽  
Pressure Region ◽  
Two Phases

Drag force on surface piercing flat plates oriented normal to a flow has been modeled using Ansys CFX v12.1 and compared to experimental results. Surface piercing refers to a body which is subjected to a two phase external flow, with the surface being the boundary between the two phases, in this case water and air. It is known that at high velocities flow behind a water piercing flat plate will separate due to a low pressure region created in the wake of the plate. This is known as the mechanism of ventilation. Once ventilation occurs, profile drag is decreased on the plates, due to the back side of the plate being exposed to air and thus atmospheric pressure. However, for surface piercing flow energy is dissipated in the form of waves and spray which increases the drag. The resulting change in drag can be expressed as a surface piercing drag coefficient of a plate, which changes as a function of speed or Froude Number and has been empirically shown to fluctuate from approximately 1.1 to 1.7 for a square plate. (Hoerner) The aim of the report is to verify and present the CFD results for surface piercing drag at a range of speeds from 0–10 m/s (0–36 kph). The results for a fully simulated domain are compared to experimental results at speeds of 0–3 m/s. One rectangular plate of aspect ratio 1 was tested in a towing tank and speed was limited. For speeds of 1–3 m/s the comparison was within 10%.

Numerical Investigations of Cooling Enhancement With Internal Ribs and External Coolant Film

2012 ◽  
Author(s):  
Zhixin Feng ◽  
Zhongwang Dou ◽  
Jianhua Wang ◽  
Shiyan Ma ◽  
Zhiqiang Zhang
Keyword(s):  
Film Cooling ◽  
Influence Factors ◽  
Numerical Approach ◽  
Cooling Effectiveness ◽  
Numerical Investigations ◽  
Wall Film ◽  
Ansys Cfx ◽  
Cooling Enhancement ◽  
Energy Equations ◽  
Cooling Air

Experimental and numerical investigations were carried out to study the average cooling performance of two different rectangular structures: 1) purely ribbed channel (only ribs were periodically embedded inner the wall of the structure); 2) combined structure of film cooling with the ribs (in the ribbed wall, film holes were periodically drilled). To create a similar environment of gas turbine blade, the experiments were performed at a high temperature mainstream, and the ambient temperature cooling air passed through the channel with the direction normal to the mainstream. In the experimental and numerical investigations, the overall cooling effect contributed by the heat conduction through channel’s wall and convections including internal ribbed wall and external film cooling was considered. In the numerical investigation, 3D conservation equations including mass, momentum, energy, turbulence eddy frequency and turbulence kinetic energy equations were solved with ANSYS-CFX, and the hybrid mesh technique and shear stress transport (SST) k-ω model were adopted. This numerical approach was validated by the experimental data. Using the validated numerical approach, the influence factors on the overall cooling effectiveness are discussed, and the effects of the internal ribs and external film cooling are numerically compared by the two structures. The relationship of the overall cooling effectiveness averaged over the rectangular surface with the mainstream Reynolds number, mass flow ratio and temperature ratio of the mainstream to cooling air, as well as the blowing ratio injected through the film holes was fitted by the numerical results.

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