Lectures on Experimental Aerodynamics

Lectures on Experimental Aerodynamics

The lectures attempt to provide an overview of image-based aerodynamics measurement techniques and their applications for students and researchers. 

The following topics are included. 
  1. Pressure and temperature sensitive paints (PSP and TSP),
  2. Physics-based optical flow method for extraction of velocity fields from flow visualization images,
  3. Global skin-friction diagnostics based on surface flow visualizations with luminescent oil, sublimation coating, TSP and PSP,
  4. Photogrammetry/videogrammetry for measurements of static and dynamic model deformation and attitudes,
  5. Relevant topics including skin-friction topology, avian wing geometry and kinematics, comparative scaling of fixed and flapping flyers, wing flow control, and oil droplet deposition in turbulent flow.

Pressure Temperature Sensitive Paints

Outline
  • Historical remarks on PSP/TSP
  • Foundations of PSP/TSP
  • Intensity-based measurement and uncertainty analysis based on PSP system modeling
  • Lifetime-based measurement and uncertainty
  • Photogrammertry and integration with PSP/TSP
  • Applications of PSP/TSP
  • Conclusions

Full lecture

Fluid Flow and Optical Flow

Objective -
To develop a general theoretical framework for extracting velocity fields from various flow visualization images
  • Projected motion equation and optical flow equation
  • Variational formulation and Euler-Lagrange equations
  • Numerical algorithms
  • Application to various flow visualizations

 

Full Lecture

Extraction of Skin Friction Fields from Surface Flow Visualizations as an Inverse Problem

Objective -
To extract high-resolution skin friction fields from surface flow visualization images by using a unified approach of optical flow
  • Global luminescent oil-film (GLOF) visualization
  • Surface heat transfer visualization with TSP
  • Surface mass transfer visualization with PSP and sublimating coatings in air and dye in water

Full Lecture

Skin Friction Topology in a Region Enclosed by Penetrable Boundaries

Objectives -
  • To obtain high-resolution skin friction fields in regions with penetrable boundaries on surface in complex 3D separated flows
  • To examine the skin friction topology by application of the Poincare-Bendixson index formula

Full lecture

Global Skin Friction Diagnostics Using Temperature Sensitive Paint

Objective -
To explore the feasibility of global skin friction diagnostic based on surface temperature measurement using temperature sensitive paint (TSP)
Current State -
  • Skin friction is the most difficult surface quantity to measure in aerodynamics and fluid mechanics
  • Global skin friction diagnostic is highly desirable in studies of complex flows

Full Lecture

Global Skin Friction Diagnostics Based on Surface Mass-Transfer Visualizations

Objective -
To explore the feasibility of global skin friction diagnostic based on surface mass-transfer visualizations
Current State -
  • Global luminescent oil-film skin friction meter
  • Global skin friction diagnostics based on surface heat-transfer/temperature visualizations

Full lecture

Skin Friction Topology of Wing-Body Junction Flows

Objectives -
  • To obtain high-resolution skin friction fields in wing-body junction flows from luminescent oil-film images taken at multiple viewing angles and positions
  • To examine the skin friction topology of wing-body junction flows based on the topological rules

Full lecture

Skin Friction Fields on Delta Wings

Objective -
To map skin friction fields on a 65˚ Delta wing and a 76/40˚ double-Delta wing using a global luminescent oil skin friction meter

Skin Friction Fields and Surface Dye Patterns on Delta Wings in Water Flows

Objective - 
To extract high-resolution skin friction fields from surface luminescent dye visualizations in water flows

Skin Friction Structures Extracted from Surface Pressure Gradient Field

Objective -
To study the feasibility of extracting skin friction structures from surface pressure gradient field

Flow Structures Extracted from Visualization Images: Vector Fields and Topology

Full lecture

Comparison between Optical Flow and Cross-Correlation Methods for Extraction of Velocity Fields from Particle Images

Objective - 
To quantitatively compare the optical flow method and cross-correlation method in extraction of velocity vectors from particle images

Temperature Sensitive Paint Heat Flux Measurements in Hypersonic Tunnels

Objective -
To develop data-reduction methods and algorithms for the determination of heat flux fields from transient temperature sensitive paint (TSP) measurements in hypersonic tunnels particularly in the Purdue Mach-6 Quiet Ludwieg Tube

Videogrammetric Technique for Aerospace Applications: From Model Attitude and Deformation to Surface Geometry

Objectives -
  • Measurement of attitudes and positions of models and control surface
  • Measurement of static and dynamic aerolastic deformation and extracting vibration modes
  • Mapping surface qualities onto surface
  • Reconstruction of 3D velocity fields

Full lecture

Thin Wing Vibration Control Using Flexible Fins

Objective -
Study thin wing vibration control using flexible fins based on high-speed videogrammetry and PIV measurements

Effects of Flexible Fin on Low-Frequency Oscillation in Post-Stalled Flows

Objectives-
  • Develop a simple passive device to suppress the natural low-frequency oscillation and reduce drag in deep stall
  • Explore the physical mechanisms

Full lecture

Avian Wing Geometry and Kinematics

Objectives -
  • Recover avian wing geometry from non-contact laser scanning surface measurements
  • Extract avian wing kinematics from videos of flying birds
  • Give analytical expressions for avian wing geometry and kinematics for computational and experimental studies

Full lecture

Comparative Scaling of Birds and Aircraft

Full Lecture

Fluid Mechanics of Deposition of Micron Liquid Droplets on Wall in Impinging Turbulent Air Jet

Objectives -
To understand the physical mechanisms of micron oil droplet deposition in an impinging turbulent jet based on measurements and theoretical analysis
  • Flow structures and formation of droplet deposition ring patterns
  • Droplet collisions induced by small-scale turbulence

Full lecture

Determining Aerodynamic Loads Based on Optical Deformation Measurements

Objective -
To develop an optical technique for remote, non-contact measurement of aerodynamic loads

Videogrammetric Determination of Aircraft Position and Attitude for Vision-Based Autonomous Landing

Objectives -
  • To study videogrammetric methods for vision-based landing based on natural ground features
  • To develop algorithms for virtual reality simulation and real flight control system
  • To evaluate the accuracy of videogrammetric methods

Full Lecture

Flight Testing: Measurements and Design

What is Flight Testing?

  • Flight testing is the process of gathering information (or data) which will accurately describe the capabilities of a particular type of airplane, and which can be used to accurately predict and optimize the use of all airplanes of that same type in future missions.
  • Flight testing of research airplanes constitutes the gathering of data in regions of the flight environment where little past information has been obtained. This information is then used to design future airplanes that can operate safely in this new environment.
  • Flight testing is at the end of the aircraft design process and is a unique part of it.

Full Lecture

Image-Based Aerodynamics Measurements - Transfer from Aerospace to Automotive Applications

Objective - 
To develop unified global high-resolution flow diagnostics tools for automotive and aerospace applications

Full Lecture

Computer Vision and Measurements in Aerospace Applications

Objective -
To build a unified theoretical framework for quantitative image-based measurements of morphology and motion fields of deformable bodies like fluids
  • Geometric Structures: Points, Curves, Surfaces
  • Motion Fields: Points, Curves, Surfaces (Geometric Flow) Complex Continuous Patterns
Full Lecture