Wing-in-ground effect (WIG) vehicles offer an exciting capability to fill the enormous
void between speed of an aircraft and the payload capacity of a ship. WIG vehicles
would be able to move cargo and passengers faster than a ship and more economical
than an aircraft. Ground effect is a phenomenon that occurs on all wings flying close
to the ground or a surface.
The aim of this project is to investigate the behavior of wings (NACA/DHMTU series)
in ground effect (on a fixed/variable terrain) using Fluent CFD package. The NACA
0012 and DHMTU series used in this project are designed specifically to fly in close
proximity to the ground.
The performance of the NACA/ DHMTU airfoils is examined for the lift and the drag
coefficients at different altitudes with varying angle of attack. The results are
compared to experimental data that is available to assess the accuracy of the CFD
simulation.
Table of Contents
1 Introduction
1.1 Background
1.2 Literature Review
1.2.1 History
1.2.2 Present Research and Development
1.3 Objectives
1.4 Research Methodology
2 Mesh Generation in GAMBIT
2.1 Mesh Design – 2D
2.1.1 Known Parameters
2.1.2 Inlet Velocity Calculation
2.1.3 Boundary Layer Calculation
2.1.4 Mesh Design I
2.1.5 Mesh Design II
2.1.6 Mesh Design III (Final)
2.2 Mesh Design – 3D
2.2.1 Mesh Design I
2.2.2 Mesh Design II
2.2.3 Mesh Design III
2.2.4 Final Mesh Design
3 Fluent
3.1 Turbulence Models
3.2 Solver Settings
3.3 Boundary Conditions – 2D
3.4 Boundary Conditions – 3D
3.5 Convergence Criteria
3.6 Mesh Adaption
4 Results and Discussion – 2D Case
4.1 Mesh Sensitivity – 2D
4.1.1 NACA Airfoil Case
4.1.2 DHMTU Airfoil Case
4.2 Aerodynamics Performance at different h/c and AoA
4.3 NACA
4.3.1 Lift
4.3.2 Drag
4.3.3 Aerodynamic Efficiency
4.4 DHMTU
4.4.1 Lift
4.4.2 Drag
4.4.3 Aerodynamic Efficiency
4.5 Comparison
4.5.1 Lift
4.5.2 Drag
4.5.3 Aerodynamic Efficiency
4.6 Conclusions
5 Results and Discussions – 3D Case
5.1 Mesh Sensitivity – 3D
5.2 Conclusions
6 Further Work
7 References
Objectives and Scope
The primary objective of this project is to investigate the aerodynamic performance of airfoils in ground effect (WIGE) using Computational Fluid Dynamics (CFD). The research specifically examines the influence of varying height-to-chord ratios and angles of attack on lift and drag coefficients, comparing standard NACA 0012 airfoils with specialized DHMTU airfoil sections in both two-dimensional and three-dimensional configurations.
- Analysis of chord-dominated ground effect using 2D airfoil sections.
- Investigation of span-dominated ground effect through 3D wing modeling.
- Comparative performance evaluation of NACA and DHMTU airfoil geometries.
- Evaluation of various turbulence models (SA, KER, KWSST, RSM) for simulation accuracy.
- Validation of CFD simulation results against experimental wind tunnel data.
Excerpt from the Book
1.1 Background
In order to understand ground effect first we need to understand the creation of lift. Wing generates lift due to the pressure difference between the upper and lower surface. High pressure flow beneath the wing tries to flow around the wing tip to low pressure flow above the wing. This motion is known as wing tip vortex. The wing tip vortices generated induces downwash, which in turn reduces the amount of lift produced by the wing. When the aircraft is flying close to the ground the wing tip vortices are only partially developed which means that the strength of the downwash created while operating close to the ground is less than the one created in freestream. So the lift produced by the wing is not affected on a greater extent and we say it increases near the ground.
Wing in Ground Effect (WIGE) vehicles are ones that fly in close proximity to the ground, usually at altitudes that are a fraction of their wing span. This effect causes an increase in overall lift and a decrease in overall drag experienced by the aircraft. Ground Effect is a combination of two different phenomena, chord dominated ground effect and span dominated ground effect. Chord dominated ground effect is associated with increase in lift and span dominated ground effect is associated with decrease in drag.
Summary of Chapters
1 Introduction: Provides an overview of the ground effect phenomenon and the history of Wing-in-Ground Effect (WIGE) vehicle development, setting the stage for the project objectives.
2 Mesh Generation in GAMBIT: Details the geometry creation and the systematic mesh design process for both 2D and 3D computational domains.
3 Fluent: Explains the underlying physical conservation equations and the specific setup parameters used in the Fluent CFD solver.
4 Results and Discussion – 2D Case: Presents a comprehensive mesh sensitivity study and performance analysis of NACA and DHMTU airfoils in two dimensions.
5 Results and Discussions – 3D Case: Discusses the computational modeling of 3D wings, evaluating different mesh variants and turbulence models to capture spanwise effects.
Keywords
Computational Fluid Dynamics, CFD, Ground Effect, WIGE, NACA 0012, DHMTU, Lift Coefficient, Drag Coefficient, Aerodynamic Efficiency, Turbulence Models, Mesh Generation, Fluent, GAMBIT, Wing Tip Vortex, Aerodynamics
Frequently Asked Questions
What is the core focus of this research?
The research focuses on investigating how wings perform when flying in close proximity to the ground (ground effect), utilizing computational fluid dynamics to simulate airflow and aerodynamic forces.
Which airfoil types are analyzed?
The study analyzes the standard NACA 0012 airfoil and the specialized DHMTU airfoil series, which is specifically designed for low-altitude ground-effect flight.
What is the primary objective regarding performance metrics?
The primary goal is to determine the impact of height-to-chord (h/c) ratios and angles of attack on the lift and drag coefficients to improve overall aerodynamic efficiency.
Which software tools were employed for the analysis?
The research used GAMBIT for geometry and mesh generation and the Fluent CFD software package for fluid flow simulation.
What does the main body of the report cover?
The main body covers mesh design methodologies for 2D and 3D spaces, the selection and implementation of turbulence models, and detailed comparative results of aerodynamic performance.
What are the key technical parameters for the study?
Key parameters include the Reynolds number, height-to-chord ratios ranging from 0.1 to 1.0, and angles of attack up to 10 degrees.
How did the author handle the limitations of the DHMTU geometry?
The author identified and corrected errors in the mathematical equations translated from Russian, ensuring the geometry accurately reflected the intended airfoil profile.
What was the observation regarding turbulence models in the 3D case?
The K-w SST (KWSST) model was found to be the most reliable, capturing the drag coefficient with a high degree of accuracy compared to the other models tested.
What conclusion was drawn about the effect of 3D modeling?
3D modeling provided significantly more accurate results compared to 2D simulations, as it better accounted for the spanwise effects and vortex behavior occurring at the wingtips.
- Arbeit zitieren
- Gulraiz Ahmed (Autor:in), 2008, Investigation of Wings in Ground Effect using Computational Fluid Dynamics, München, GRIN Verlag, https://www.grin.com/document/196922
