Revised Attachment 1.A - NFAC Test Planning Additional Information.pdf

APPENDIX 1.A - Additional Information for NFAC Test Planning

1. Measurement & diagnostics for the high-Reynolds number airfoil Minimum Test Matrix

Force Measurements

• Loads balance – may need to be locked depending on airfoil loads and model mounting system

• Strain gauges

Pressure measurements

• Pressure rakes and probes - single and multi-component probes

• Wall pressure sensors within 40 x 80 test section

• Pressure transducers – Mensor 6100 high precision – 9 available with variety of pressure ranges

• 64 port pressure scanning systems with a variety of pressure ranges

Velocity measurements

• Hot wire and hot-film measurement systems

• Particle image velocimetry systems

• Ultrasonic anemometers – Gill R3-100

Temperature measurements

• Infrared thermography

• Resistance temperature detectors

• Static thermocouples

Multifunction Standard Air Data & Fast Response Probes: five-hole probes, w/ varying frequency response

• Velocity

• Flow Angle

• Pressure

• Humidity

• Temperature

• Photogrammetry for probe deflection measurement

Standard Tunnel Conditions:

• Two static rings upstream of test section

• Dynamic pressure

• Total temperature

• Dew-point temperature/relative humidity

• Barometric pressure

Other Items

• Accelerometers

• Inclinometers

• Flow Meters

• Encoders

• Displacement Sensors (LVDT, LVIT, Potentiometer, etc)

Wind tunnel data acquisition system information

• Detailed in van Aken, J. and Yang, L., “Development of a new State-of-the-Art Data Acquisition System for the National Full-Scale Aerodynamics Complex Wind Tunnels,” 47th AIAA Aerospace Sciences Meeting, Orlando, FL, 5-8 January 2009, AIAA-2009-1346.

• Any analog signal between ±10V can be acquired by data acquisition system

2. Preliminary Test Article Fabrication Cost Estimates (to use as planning guidance only) Estimates for ~10m x 3m model: ~$500 - $600k

• Conventional model built like a blade (CNC mold + metal frame, composite infused layup, internal structure, surface finish): ~$200k/model

• Additional costs: structural and other interface requirements for facility integration (design and fabrication);

shipping and handling; special surface finishing and QA given sensitivity of aero results at this scale and Reynolds number: ~$150-$200k

• 3D printing or other model construction methods that skip the need for a mold would likely reduce costs

• Instrumentation hardware and labor costs: $150K (assumes scanners and DAQ h/w, s/w from NFAC partially)

3. Preliminary NFAC 40’x80’ test section inflow section characterization of turbulence (courtesy of Dr. Emily Sayles, NFAC)

A recent 40- by 80-Foot Wind Tunnel flow survey acquired long-duration time histories of three-dimensional velocity fluctuations at and near the center of the test section. Velocity spectra contain appreciable energy below 1 Hz. This low frequency unsteadiness is referred to as flow meander and is generated by phenomena with periods on the order of 10 seconds. Since the wavelengths associated with these low frequencies are much larger than the test section’s dimensions, a high-pass filter was applied to the velocity time traces before calculating turbulence intensities and integral length scales. The filtered velocity time traces produce turbulence intensities ranging from

0.2 to 0.7%. Integral length scale estimates in the streamwise (longitudinal) direction are 0.5 ft for the streamwise velocity component, and 1.5 ft for the lateral and vertical velocity components.