scholarly journals High-order computational fluid dynamics tools for aircraft design

2014 ◽  
Vol 372 (2022) ◽  
pp. 20130318 ◽  
Author(s):  
Z. J. Wang
Keyword(s):  
Fluid Dynamics ◽  
Growth Rate ◽  
Computational Fluid Dynamics ◽  
Fuel Economy ◽  
Aircraft Design ◽  
Aircraft Engine ◽  
Foreseeable Future ◽  
Complex Flows ◽  
Environmental Goals ◽  
Set Up

Most forecasts predict an annual airline traffic growth rate between 4.5 and 5% in the foreseeable future. To sustain that growth, the environmental impact of aircraft cannot be ignored. Future aircraft must have much better fuel economy, dramatically less greenhouse gas emissions and noise, in addition to better performance. Many technical breakthroughs must take place to achieve the aggressive environmental goals set up by governments in North America and Europe. One of these breakthroughs will be physics-based, highly accurate and efficient computational fluid dynamics and aeroacoustics tools capable of predicting complex flows over the entire flight envelope and through an aircraft engine, and computing aircraft noise. Some of these flows are dominated by unsteady vortices of disparate scales, often highly turbulent, and they call for higher-order methods. As these tools will be integral components of a multi-disciplinary optimization environment, they must be efficient to impact design. Ultimately, the accuracy, efficiency, robustness, scalability and geometric flexibility will determine which methods will be adopted in the design process. This article explores these aspects and identifies pacing items.

Reduced Aerodynamic Drag for Truck-Trailer Configurations Using Parametrized CFD Studies

2012 ◽  
Author(s):  
Srdan Pavlović ◽  
Magnus Andersson ◽  
Jonas Lantz ◽  
Matts Karlsson
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Reduction ◽  
Conceptual Design ◽  
Fuel Economy ◽  
Aerodynamic Drag ◽  
Foreseeable Future ◽  
Heavy Duty ◽  
Computational Fluid Dynamics Cfd

In the presented work, two studies using Computational Fluid Dynamics (CFD) have been conducted on a generic truck-like model with and without a trailer unit at a speed of 80 km/h. The purpose is to evaluate drag reduction possibilities using externally fitted devices. A first study deals with a flap placed at the back of a rigid truck and inclined at seven different angles with two lengths. Results show that it is possible to decrease drag by 4%. In a second study, the flap has been fitted on the tractor and trailer units of a truck-trailer combination. Four settings were surveyed for this investigation, one of which proved to decrease drag by up to 15%. A last configuration where the gap between the units has been closed has also been evaluated. This configuration offers a 15% decrease in drag. Adding a flap to the closed gap configuration decreases drag by 18%. New means of reducing aerodynamic drag of heavy-duty (HD) vehicles will be important in the foreseeable future in order to improve the fuel economy. The possibilities of reducing drag are prevalent using conceptual design.

scholarly journals Simulating Smoke Filling in Big Halls by Computational Fluid Dynamics

2011 ◽  
Vol 2011 ◽  
pp. 1-16 ◽  
Author(s):  
W. K. Chow ◽  
C. L. Chow ◽  
S. S. Li
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Construction Projects ◽  
Far East ◽  
Mainland China ◽  
Convergence Criteria ◽  
Key Points ◽  
Set Up ◽  
Relaxation Factors ◽  
Smoke Filling

Many tall halls of big space volume were built and, to be built in many construction projects in the Far East, particularly Mainland China, Hong Kong, and Taiwan. Smoke is identified to be the key hazard to handle. Consequently, smoke exhaust systems are specified in the fire code in those areas. An update on applying Computational Fluid Dynamics (CFD) in smoke exhaust design will be presented in this paper. Key points to note in CFD simulations on smoke filling due to a fire in a big hall will be discussed. Mathematical aspects concerning of discretization of partial differential equations and algorithms for solving the velocity-pressure linked equations are briefly outlined. Results predicted by CFD with different free boundary conditions are compared with those on room fire tests. Standards on grid size, relaxation factors, convergence criteria, and false diffusion should be set up for numerical experiments with CFD.

scholarly journals Study of the Secondary Flow in Aircraft Engine Compressor Disks using Computational Fluid Dynamics

2018 ◽  
Vol 6 (1) ◽  
pp. 85-104
Author(s):  
Syed Naveed Ahmed ◽  
P. Ravinder Reddy ◽  
Sriram Venkatesh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Secondary Flow ◽  
Aircraft Engine ◽  
Temperature Gradients ◽  
Design Parameters ◽  
Engine Fuel ◽  
Core Flow ◽  
The Impact ◽  
Compressor Disk

The compressor disks of an aircraft engine which operate at very high rotational speeds are exposed to significant temperature gradients. These temperature gradients induce thermal stresses into the rotating disks which along with the existing dynamic stresses significantly reduce their useful field life. Hence it becomes essential to reduce the disk temperature gradients by utilizing a certain percentage of the compressor core flow known as the secondary flow for either heating or cooling these rotating parts. But this extraction of the compressor core flow results in a higher engine fuel burn for a given engine thrust.  Hence the need arises for a better utilization of the secondary flow to effectively reduce the temperature gradients of the rotating compressor disks. As the secondary flow thermal phenomenon  inside the rotating compressor disk cavities is very complex and due to it’s direct impact on the  life expectancy of the disks it becomes critical to understand it’s  thermo-fluid behaviour by the effective use of available Computational Fluid Dynamic tools. In the current study the secondary flow through the compressor disk cavities is simulated using Computational Fluid Dynamics (CFD) and the results are analysed and reported. The analysis of these results help in a better understanding of the distribution of the flow and the variations of the thermal fluid parameters across the secondary flow system. These results are also later used as thermal boundary conditions in the Finite Element model (FEM) to study the impact of various engine design parameters on the disk temperature gradients after being validated by the experimental results. The findings from this computer aided investigation offers support in make design improvements aimed at lowering the disk temperature gradients and enhancing their useful field life

Computational fluid dynamics study of Savonius rotors using OpenFOAM

2020 ◽  
pp. 0309524X2092495
Author(s):  
Federico González Madina ◽  
Alejandro Gutiérrez ◽  
Pedro Galione
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Dynamics Simulation ◽  
Power Coefficient ◽  
Small Scale ◽  
Two Dimensional ◽  
Discretization Schemes ◽  
Set Up

In this work, two-dimensional models of Savonius rotors are simulated using OpenFOAM® in order to predict the aerodynamic performance of small-scale vertical-axis wind turbines. The results are reported analyzing the aerodynamic performance and forces acting on the rotors. Power coefficient, [Formula: see text], is compared with experimental data for each operation point, and for three different geometries. Simulations with first- and second-order discretization schemes are carried out and compared, both quantitative and qualitative. Since usual grid dimensions result not to be suitable for simulations of Savonius rotors, an analysis of different domains is performed and compared. Finally, a set up for computational fluid dynamics simulation of two-dimensional Savonius rotors is proposed. The fluid–rotor interaction is analyzed and the vortex shedding is correlated with [Formula: see text] values and wake description.

scholarly journals Mapping flow distortion on oceanographic platforms using computational fluid dynamics

Ocean Science ◽  
2013 ◽  
Vol 9 (5) ◽  
pp. 855-866 ◽  
Author(s):  
N. O'Sullivan ◽  
S. Landwehr ◽  
B. Ward
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Speed ◽  
Close Agreement ◽  
Velocity Fields ◽  
Experimental Measurements ◽  
Flow Distortion ◽  
Direct Measurements ◽  
Computational Fluid Dynamics Cfd ◽  
Set Up

Abstract. Wind speed measurements over the ocean on ships or buoys are affected by flow distortion from the platform and by the anemometer itself. This can lead to errors in direct measurements and the derived parametrisations. Here we computational fluid dynamics (CFD) to simulate the errors in wind speed measurements caused by flow distortion on the RV Celtic Explorer. Numerical measurements were obtained from the finite-volume CFD code OpenFOAM, which was used to simulate the velocity fields. This was done over a range of orientations in the test domain from −60 to +60° in increments of 10°. The simulation was also set up for a range of velocities, ranging from 5 to 25 m s−1 in increments of 0.5 m s−1. The numerical analysis showed close agreement to experimental measurements.

Perspective: Future Research Directions in Computational Fluid Dynamics

1994 ◽  
Vol 116 (2) ◽  
pp. 212-215 ◽  
Author(s):  
R. W. Douglass ◽  
J. D. Ramshaw
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Future Research ◽  
Complex Flows ◽  
Research Directions ◽  
Simulation Research ◽  
Current State ◽  
Future Research Directions ◽  
Computational Fluid Dynamics Cfd ◽  
Real Fluids

The current state of computational fluid dynamics (CFD) has yet to reach its full promise as a general tool for engineering design and simulation. Research in the areas of code robustness, complex flows of real fluids, and numerical errors and resolution are proposed as directions aiming toward that goal. We illustrate some of the current CFD challenges using selected applications.

VIV Prediction of a Truss Spar Pull-Tube Array Using CFD

2011 ◽  
Author(s):  
Yiannis Constantinides ◽  
Weiwei Yu ◽  
Samuel Holmes
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Structural Model ◽  
Full Scale ◽  
Complex Flows ◽  
Single Cylinder ◽  
Structure Interaction ◽  
Cylinder Arrays ◽  
Truss Spar ◽  
Computational Fluid Dynamics Cfd

Complex flows through cylinder arrays, such as the case of pull-tubes located in the truss section of a truss spar, are very difficult to describe and analyze. It is especially difficult to predict and correct Vortex Induced Vibration (VIV) response using traditional tools that were developed to analyze single cylinder rather than arrays of cylinders. Computational Fluid Dynamics (CFD) offers the designer the ability to properly analyze these complex problems and increase the reliability of his design. In this study, a full scale truss spar with pull-tubes is modeled using CFD coupled with an FEA structural model of the pull-tubes for a fluid-structure interaction (FSI) computation. The VIV response of the pull-tubes is predicted and analyzed for different current headings and speeds.

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