Compressing Aerodynamic Hazard Data

2022 ◽  
Author(s):  
Yang Zhou ◽  
Nicolas Boullé ◽  
David Barton ◽  
Eduard Campillo-Funollet ◽  
Cameron Hall
Keyword(s):  
Cfd Simulation ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Data Streaming ◽  
Compression Method ◽  
Simulation Data ◽  
Geometrical Features ◽  
Computational Fluid Dynamics Cfd ◽  
Volume Compression ◽  
And Control

Data compression of three-dimensional computational fluid dynamics (CFD) simulation data is crucial to allow effective data-streaming for drone navigation and control. This problem is computationally challenging due to the complexity of the geometrical features present in the CFD data, and cannot be tackled by standard compression techniques such as sphere-tree. In this report, we present two different methods based on octree and cuboid primitives to compress velocity isosurfaces and volumetric data in three dimensions. Our volume compression method achieves a 1400 compression rate of raw simulation data and allows parallel computing.

Adaptive Geometry Representation of Turbine Vane Frames for Use in Optimization

2021 ◽  
Author(s):  
Sebastian F. Riebl ◽  
Christian Wakelam ◽  
Reinhard Niehuis
Keyword(s):  
Design Space ◽  
Cfd Simulation ◽  
A Priori ◽  
Three Dimensional ◽  
Optimization Method ◽  
Three Dimensions ◽  
Design Parameters ◽  
Adjustment Process ◽  
Turbine Vane ◽  
Integrated Concept

Abstract Turbine Vane Frames (TVF) are a way to realize more compact jet engine designs. Located between the high pressure turbine (HPT) and the low pressure turbine (LPT), they fulfill structural and aerodynamic tasks. When used as an integrated concept with splitters located between the structural load-bearing vanes, the TVF configuration contains more than one type of airfoil with sometimes pronouncedly different properties. This system of multidisciplinary demands and mixed blading poses an interesting opportunity for optimization. Within the scope of the present work, a full geometric parameterization of a TVF with splitters is presented. The parameterization is chosen as to minimize the number of parameters required to automatically and flexibly represent all blade types involved in a TVF row in all three dimensions. Typical blade design parameters are linked to the fourth order Bézier-curve controlled camber line-thickness parameterization. Based on conventional design rules, a procedure is presented, which sets the parameters within their permissible ranges according to the imposed constraints, using a proprietary developed code. The presented workflow relies on subsequent three dimensional geometry generation by transfer of the proposed parameter set to a commercially available CAD package. The interdependencies of parameters are discussed and their respective significance for the adjustment process is detailed. Furthermore, the capability of the chosen parameterization and adjustment process to rebuild an exemplary reference TVF geometry is demonstrated. The results are verified by comparing not only geometrical profile data, but also validated CFD simulation results between the rebuilt and original geometries. Measures taken to ensure the robustness of the method are highlighted and evaluated by exploring extremes in the permissible design space. Finally, the embedding of the proposed method within the framework of an automated, gradient free numerical optimization is discussed. Herein, implications of the proposed method on response surface modeling in combination with the optimization method are highlighted. The method promises to be an option for improvement of optimization efficiency in gradient free optimization of interdependent blade geometries, by a-priori excluding unsuitable blade combinations, yet keeping restrictions to the design space as limited as possible.

CFD SIMULATION OF SHEAR STRESS AND SECONDARY FLOWS IN URETHRA

2007 ◽  
Vol 19 (02) ◽  
pp. 117-127 ◽  
Author(s):  
Yang-Yao Niu ◽  
Ding-Yu Chang
Keyword(s):  
Shear Stress ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Normal Female ◽  
Urinary System ◽  
Stress Distributions ◽  
Computational Fluid Dynamics Cfd ◽  
Peak Value ◽  
Lower Urinary

In this work, a preliminary numerical simulation of the lower urinary system using Computational Fluid Dynamics (CFD) is performed. Very few studies have been done on the simulation of three-dimensional urine through the lower urinary system. In this study, a simplified lower urinary model with rigid body assumption is proposed. The distributions of urine flow velocity, wall pressure and shear stress along the urethra are simulated based on MRI scanned uroflowmetry of a normal female. Numerical results show that violent secondary flows appear on the cross surface near the end of the urethra when the inflow rate is increased. The oscillative variation of pressure and shear stress distributions are found around the beginning section of the urethra when flow rate is at the peak value.

Hydraulic Characteristics of the New Type Bulb Turbine With Micro-Head

2013 ◽  
Author(s):  
Lingyu Li ◽  
Yuan Zheng ◽  
Daqing Zhou ◽  
Zihao Mi
Keyword(s):  
Numerical Simulation ◽  
Cfd Simulation ◽  
Guide Vane ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Three Dimensions ◽  
Guide Vanes ◽  
Runner Blade ◽  
Cfd Method ◽  
Bulb Turbine

The head of low-head hydropower stations is generally higher than 2.5m in the world, while micro-head hydropower resources which head is less than 2.5m are also very rich. In the paper, three-dimensional CFD method has been used to simulate flow passage of the micro-head bulb turbine. The design head and unit flow of the turbine was 1m and 3m3/s respectively. With the numerical simulation, the bulb turbine is researched by analyzing external characteristics of the bulb turbine, flow distribution before the runner, pressure distribution of the runner blade surface, and flow distribution of the outlet conduit under three different schemes. The turbine in second scheme was test by manufactured into a physical model. According to the results of numerical simulation and model test, bulb turbine with no guide vane in second scheme has simpler structure, lower cost, and better flow capacity than first scheme, which has traditional multi-guide vanes. Meanwhile, efficiency of second scheme has just little decrease. The results of three dimensions CFD simulation and test results agree well in second scheme, and higher efficiency is up to 77% which has a wider area with the head of 1m. The curved supports in third scheme are combined guide vanes to the fixed supports based on 2nd scheme. By the water circulations flowing along the curved supports which improve energy transformation ability of the runner, the efficiency of the turbine in third scheme is up to 82.6%. Third scheme, which has simpler structure and best performance, is appropriate for the development and utilization of micro-head hydropower resources in plains and oceans.

How Computational Grid Refinement in Three Dimensions Affects CFD-DEM Results for Psuedo-2D Fluidized Gas-Solid Beds

2017 ◽  
Author(s):  
Annette Volk ◽  
Urmila Ghia
Keyword(s):  
Three Dimensional ◽  
Computational Grid ◽  
Three Dimensions ◽  
Computational Grids ◽  
Grid Refinement ◽  
2D Simulation ◽  
Computational Fluid Dynamics Cfd ◽  
Bed Thickness ◽  
Simulation Results ◽  
Accuracy Of Results

Computational Fluid Dynamics (CFD)-Discrete Element Method (DEM) simulations are designed to model a pseudo-two-dimensional fluidized bed. Bed behavior and accuracy of results are shown to change as the simulations are conducted on increasingly refined computational grids. Trends of the results with grid refinement are reported for both three-dimensional, uniform refinement, and for grid refinement in only the direction of bed thickness. Pseudo-2D simulation results are examined against previously published experimental data to assess relative accuracy compared to fully 3D simulation results. Two drag laws are employed in the simulations, resulting in different trends of results with computational grid refinement. From these results, we present suggestions for accurate model design.

The simulation of single wraparound fin on a semi-cylindrical missile body

2020 ◽  
Vol 92 (3) ◽  
pp. 418-427 ◽  
Author(s):  
Nayhel Sharma ◽  
Rakesh Kumar
Keyword(s):  
Research Study ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Future Research ◽  
Aerodynamic Coefficients ◽  
Content Type ◽  
Computational Fluid Dynamics Cfd ◽  
Predicted Values ◽  
Characteristic Trend ◽  
Practical Implications

Purpose The purpose of this paper is to establish a freestream computational fluid dynamics (CFD) model of a three-dimensional non-spinning semi-cylindrical missile model with a single wrap around fin in Mach 2.70-3.00M range and 0° angle of attack, and ultimately establishing itself for future research study. Design/methodology/approach In this study, the behaviour of flow around the fin was investigated using a κ-ϵ turbulence model of second-order of discretization. This was done using a highly structured mesh. Additionally, an inviscid CFD simulation involving the same boundary conditions have also been carried out for comparison. Findings The obtained values of aerodynamic coefficients and pressure contours visualizations are compared against their experimental and computational counterparts. A typical missile aerodynamic characteristic trend can be seen in the current CFD. Practical implications The predicted values of the aerodynamic coefficients of this single fin model have also been compared to those of the full missile body comprising of four fins from the previous research studies, and a similar aerodynamic trend can be seen. Originality/value This study explores the possibility of the use of turbulence modelling in a single fin model of a missile and provides a basic computational model for further understanding the flow behaviour near the fin.

Transient CFD Visualization of Fossil Fuel Combustion Simulations

2003 ◽  
Author(s):  
Brian Dotson ◽  
Kent Eshenberg ◽  
Chris Guenther ◽  
Thomas O’Brien
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Cfd Simulation ◽  
Low Cost ◽  
Three Dimensional ◽  
Cfd Simulations ◽  
Projection System ◽  
Computational Fluid Dynamics Cfd ◽  
High Level ◽  
Wall System

The design of high-efficiency lower-emission coal-fed power plants is facilitated by the extensive use of computational fluid dynamics (CFD) simulations. This paper describes work conducted at the National Energy Technology Laboratory (NETL) and Pittsburgh Supercomputing Center (PSC) to provide an environment for the immersive three-dimensional visualization of CFD simulation results. A low-cost high-resolution projection system has been developed in the visualization lab at NETL. This multi-wall system consists of four projection screens, three of which are tiled into four quadrants. The graphics for the multi-wall system are rendered using a cluster of eight personal computers. A high-level visualization interface named Mavis has also been developed to combine the powerful 3D modules of OpenDX with methods developed at NETL for studying multiphase CFD data. With Python, a completely new OpenDX user interface was built that extends and simplifies the features of a basic graphics library.

scholarly journals Three-Dimensional Modeling and Control of a Tethered UAV-Buoy System

2021 ◽  
Author(s):  
Ahmad Kourani ◽  
Naseem Daher
Keyword(s):  
Control System ◽  
Three Dimensional ◽  
Vertical Motion ◽  
Robotic System ◽  
Three Dimensions ◽  
Spherical Coordinate ◽  
Nonlinear Dynamical ◽  
Modeling And Control ◽  
Three Dimensional Modeling ◽  
And Control

Abstract This work presents the nonlinear dynamical model and motion controller of a system consisting of an unmanned aerial vehicle (UAV) that is tethered to a floating buoy in the three-dimensional (3D) space. Detailed models of the UAV, buoy, and the coupled tethered system dynamics are presented in a marine environment that includes surface-water currents and oscillating gravity waves, in addition to wind gusts. This work extends the previously modeled planar (vertical) motion of this novel robotic system to allow its free motion in all three dimensions. Furthermore, a Directional Surge Velocity Control System (DSVCS) is hereby proposed to allow both the free movement of the UAV around the buoy when the cable is slack, and the manipulation of the buoy’s surge velocity when the cable is taut. Using a spherical coordinate system centered at the buoy, the control system commands the UAV to apply forces on the buoy at specific azimuth and elevation angles via the tether, which yields a more appropriate realization of the control problem as compared to the Cartesian coordinates where the traditional x- , y- , and z -coordinates do not intuitively describe the tether’s tension and orientation. The proposed robotic system and controller offer a new method of interaction and collaboration between UAVs and marine systems from a locomotion perspective. The system is validated in a virtual high-fidelity simulation environment, which was specifically developed for this purpose, while considering various settings and wave scenarios.

Optimization of CFD Meshing for Stented Vessel Geometries

2014 ◽  
Vol 553 ◽  
pp. 373-378 ◽  
Author(s):  
Azadeh Lotfi ◽  
Tracie J. Barber
Keyword(s):  
Cfd Simulation ◽  
Computational Cost ◽  
Three Dimensional ◽  
Coronary Bifurcation ◽  
Cfd Simulations ◽  
Coronary Stent Implantation ◽  
Bifurcation Stenting ◽  
Computational Fluid Dynamics Cfd ◽  
Blood Flow Patterns ◽  
High Computational Cost

Coronary stent implantation is the most widely used technique currently employed to treat atherosclerosis in coronary artery. Although the optimal technique for bifurcation stenting in terms of clinical outcome is still open to controversy, most previous studies have focused on the single-stenting techniques due to its simpler geometry and easier clinical implantation. While the biomedical environment in a stented coronary bifurcation is extremely challenging to model, Computational Fluid Dynamics (CFD) investigations have been used to study the effect of stent on blood flow patterns, however, in CFD simulation of double-stenting techniques, the presence of two or more stents accentuates the complexity of the geometry and the associated meshes especially in the region where two or multiple stent layers come together. Hence, in this study, complex three-dimensional geometric CFD simulations of a stented vessel have been performed in order to adopt an efficient and optimal meshing method to reduce the high computational cost. In doing so, several meshing strategies were chosen and applied.

scholarly journals CFD Simulation of Knock Onset in a Heavy-Duty Spark Ignition Gas Engine

2019 ◽  
Vol 8 (4) ◽  
pp. 9585-9593
Keyword(s):  
Fluid Dynamics ◽  
Numerical Model ◽  
Cfd Simulation ◽  
Combustion Process ◽  
Three Dimensional ◽  
Spark Ignition ◽  
Heavy Duty ◽  
Gas Engine ◽  
Optimization Study ◽  
Computational Fluid Dynamics Cfd

The paper describes a method for evaluating knocking onset with computational fluid dynamics (CFD) numerical model of the combustion process of spark ignited (SI) gas engine and methods for assessing the probability of knocking combustion based on this model. The probability of knocking combustion, which characterizes the boundary condition between normal combustion and knocking, is determined (8%). An optimization study of the influence of adjustment parameters on the probability of knocking based on a three-dimensional numerical model is carried out. The developed and tested technique allows one to monitor the tendency of the influence of various adjustment parameters on the probability of knocking in a SI gas engine.

Off Set Strip Fins Thermo Hydraulic Performance Analysis Through CFD Simulation

2013 ◽  
Author(s):  
Guisselle Polo ◽  
Antonio Bula
Keyword(s):  
Fluid Dynamics ◽  
Cfd Simulation ◽  
Computational Simulation ◽  
Three Dimensional ◽  
Hydraulic Performance ◽  
Constant Flow ◽  
Uniform Temperature ◽  
Colburn Factor ◽  
Computational Fluid Dynamics Cfd ◽  
And Performance

A computational simulation of the thermo hydraulic performance of a trapezoidal Off Set Strip Fin (OSF) is performed. The simulations are carried for Reynolds number ranging from 300 to 9000 considering three-dimensional conditions (3D). Calculations were developed assuming a constant flow. Colburn factor j, and the friction factor f, were calculated. Uniform temperature condition is assumed at the solid surface and at the inlet. The results have been compared with studies made by Kays and London, (1984), Manglik and Bergles (1990), and Muzychka and Yovanovich, (2001). According to the obtained results, it can be concluded that Computational Fluid Dynamics (CFD) is able to explore the behavior and performance of this kind of fin, showing that the hydraulic performance is well represented by correlations widely used in literature, while thermal performance seems to be under predicted.

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