A wind tunnel for the calibration of Mars wind sensors

Abstract

A major limitation in the development of wind sensors for use on Mars is the lack of suitable testing and calibration facilities. A low density wind tunnel has been developed at Oxford University for calibration of wind sensors for Mars landers, capable of providing stable or dynamically varying winds, of air or carbon dioxide, at Martian pressures (5-10 mbar) and speeds (0.5-30 m/s), and temperatures of 200-300 K. The flow field in the test section was calculated using analytical and computational modelling techniques, and validated experimentally using a pitot probe. This facility's stability and accuracy offer significant advantages with respect to previous calibration facilities.

Numerical study of lander effects on DREAMS scientific package measurements

“…As we have seen the nominal conditions are carbon dioxide at p = 7 mbar, T = 217 K and speed range goes from 0 m/s to 20 m/s. A low speed wind tunnel has been developed at Oxford University [16] for calibration of wind sensors for Mars landers; the flow is laminar and it can operate with air or carbon dioxide, pressure form 5 to 10 mbar, speeds from 0.5 to 30 m/s and temperature from 200 to 300 K. The limit for our application is the low section diameter (0.18 m). The Mars Wind Tunnel at Tohoku University [17] purpose is to simulate Martian flight condition; it operates with air or CO 2 at 10 mbar, at is transitional.…”

“…Other velocity measurement system have been evaluated and discarded. Hot wire anemometers need to be calibrated under Martian condition [16]; Laser-Doppler Anemometry (LDA) requires suspended flow particles (sand or vapour) and this is not compliant with our cleanliness requirements; earth acoustic anemometers need to be adapted for use under Martian conditions (main differences are the different acoustic impedance and signal attenuation between Martian environment and air [19]). Knowing the dynamic pressure p dyn , the difference between total pressure and static pressure, we can estimate the local flow speed u by means of Bernoulli law, u = (2p dyn )/ρ.…”

A Design and Construction of a Wind Tunnel for Engineering Laboratories

“…Wilson et, al, (2008) conducted a study on the wind tunnel for testing the sensor in pressures force and wind speeds. The wind tunnel that is uniform laminar flow in the test section.…”

Development of a Low-Density Wind Tunnel for Simulating Martian Atmospheric Flight

“…[7][8][9][10][11][12][13] However, these wind tunnels have been used mainly for studying geological and planetary sciences, and are not suitable for aerodynamic research. For this reason, the experimental data of airfoils regarding low Reynolds number and high subsonic flow region is very limited (Fig.…”

“…The wind tunnel is an induction-type unit and driven by a multiple-nozzle supersonic ejector. Among existing low-density wind tunnels, the Small Variable-Pressure Wind Tunnel at Nishi-Nippon Institute of Technology 7) uses a blower as the driving system and Oxford University's Low-Density Wind Tunnel (LDWT) 8) is connected to a large-volume vacuum chamber with a high-capacity vacuum pump. It is noted, however, that the compression efficiency of a blower and the exhaust efficiency of a vacuum pump decrease rapidly at low pressures.…”