Aeronautic Instruments. Section III : Aircraft Speed Instruments

Part 1 contains a discussion and description of the various types of air speed measuring instruments. The authors then give general specifications and performance requirements with the results of tests on air speed indicators at the Bureau of Standards. Part 2 reports methods and laboratory apparatus used at the Bureau of Standards to make static tests. Methods are also given of combining wind tunnel tests with static tests. Consideration is also given to free flight tests. Part 3 discusses the problem of finding suitable methods for the purpose of measuring the speed of aircraft relative to the ground

Low airspeed systems for the naval SH-60 Seahawk aircraft

Pitot-static systems have long been used to measure helicopter airspeed. The Pitot-static system is inaccurate at low airspeeds (below 40 knots) due to the limited sensitivity of the sensor and interference of rotor down wash. Additionally, the Pitot-static system only measures unidirectional airspeed and unlike its fixed wing counterparts the helicopter is not limited to flight in one direction. With the changing roles of the US Navy Seahawk it is imperative that the pilot and aircrew have all the information necessary to safely complete the mission and prolong the life of the aircraft and dynamic components. With the addition of a dipping sonar to the remanufactured SH-60B aircraft (designated SH- 60R) and the conduct of combat search and rescue mission in the Navy\u27s Seahawks the aircraft will spend more time in a hover and will be flown more aggressively than in the past. This thesis examiness the advantages of incorporating a low airspeed system into the modem helicopter, in particular the SH-60 Seahawk. The author examines the low airspeed sensors and systems currently available and gives a brief description of each system\u27s operation. The author examines the challenges of installing a low airspeed sensor onto the SH-60 Seahawk. The author has determined that either a laser velocimeter or an analytical neural network system would be the best approach for a low airspeed system for the SH-60 Seahawk. The author recommends a combined approach be taken to develop both the laser velocimeter and analytical neural network, and incorporate the best system after further flight testing

Development of an Unmanned Aerial Vehicle for Atmospheric Turbulence Measurement

An unmanned aerial vehicle was developed to study turbulence in the atmospheric boundary layer. The development of the aircraft, BLUECAT5, and instrumentation package culminated in a series of flight experiments conducted in two different locations near Stillwater, Oklahoma, USA. The flight experiments employed the use of two of the unmanned aerial vehicles flying simultaneously, each containing a five-hole pressure probe as part of a turbulence-measuring instrumentation package. A total of 18 flights were completed with the objective to measure atmospheric properties at five altitudes between 20 and 120 meters. Multiple flights were flown over two days in which the effects of the diurnal cycle on the boundary layer were investigated. Profiles for mean wind velocity, temperature, and humidity all follow expected boundary layer behavior throughout the day. Evolution of the boundary layer can be seen with the early morning, stable boundary layer identified and its transition to the early mid-day convective mixed boundary layer observed. The corresponding increase in turbulence intensity was found to be significant. The success of the test campaign demonstrated the ability of the developed unmanned system to measure turbulence in the atmospheric boundary layer

Aerometry instrumentation study Final report

Techniques and instruments for meteorological measurements in Mars and Venus atmosphere

Design and Construction of a Supersonic Wind Tunnel with Diagnostics

The goal of this project was to design, construct, and conduct preliminary testing of a supersonic wind tunnel (SWT). In addition to observing supersonic flow characteristics, behavior of test objects can be investigated. The wind tunnel is an indraft type which uses the pressure ratio created between a vacuum chamber and the ambient air to generate a flow. The SWT has a modular design, allowing users to switch the channel contours with test-specific designs. The tunnel uses a Pitot-static probe system to acquire pressure measurements, which are used to calculate Mach number. A schlieren optical system was built to allow imaging of the flow and structures within. A humidity control system was designed and built to ensure performance without condensation under a range of ambient conditions

Master of Science

thesisA booster fan is an underground ventilation device installed in series with a main surface fan and is used to boost the pressure of air of the current passing through it. Currently, federal regulations in the U.S. do not permit the use of booster fans in underground bituminous and lignite coal mines. Considering that a booster fan is an active device with moving parts, it is imperative to install it with an efficient and reliable monitoring and control system. The important aspects of booster fans and monitoring systems that are discussed in this thesis are environmental monitoring, condition monitoring, design and installation principles, guidelines for safe operation of booster fans, fan interlocking, and risk assessment. The environmental status of underground mining operations with large booster fans is critical to the health and safety of the miners. Mining operations, especially in large deep coal mines, rely greatly upon the monitoring systems to create safe and healthy work conditions by monitoring carbon monoxide, methane, carbon dioxide, oxygen, nitrogen oxides, and smoke. Condition monitoring is the process of measuring the fan operating factors to evaluate and predict the health of mining machinery. In coal mine ventilation, condition monitoring includes the measurement and evaluation of the following factors: vibration, barometric pressure, noise, input power, motor and bearing temperatures, differential pressures, and air flow rate. The monitoring system network in a mine could become extremely complex if the monitors are not located at the right place. Recommendations are given for calculating the appropriate siting and spacing of monitors. Booster fans are assembled and installed to operate under harsh conditions; they are subject to wear and tear and malfunction. Installation principles are discussed in detail and recommendations are made for the safe operation of booster fans. Interlocking is one method of preventing the occurrence of unsafe conditions due to electrical or mechanical failures. It is described in detail, and the best practices used in other coal mining countries are summarized. To ensure the safe operation of booster fans and monitoring systems underground, a risk assessment was done, critical hazards were identified, and mitigation controls are outlined

NEAR WALL SHEAR STRESS MODIFICATION USING AN ACTIVE PIEZOELECTRIC NANOWIRE SURFACE

An experimental study was conducted to explore the possible application of dynamically actuated nanowires to effectively disturb the wall layer in fully developed, turbulent channel flow. Actuated nanowires have the potential to be used for the mixing and filtering of chemicals, enhancing convective heat transfer and reducing drag. The first experimental evidence is presented suggesting it is possible to manipulate and subsequently control turbulent flow structures with active nanowires. An array of rigid, ultra-long (40 μm) TiO2 nanowires was fabricated and installed in the bounding wall of turbulent channel flow then oscillated using an attached piezoelectric actuator. Flow velocity and variance measurements were taken using a single sensor hot-wire with results indicating the nanowire array significantly influenced the flow by increasing the turbulent kinetic energy through the entire wall layer

Compressible Turbulence Measurement in the Mixing Layer of an Adiabatic Normal Slot Injection into Supersonic Flow

In this study mean flow and compressible turbulence measurements were taken at a station x = 72W downstream of the injection, where W is the injector throat width, of an adiabatic 2-D Mach 1.6 normal slot injection into a Mach 2.9 flow. Data were collected using a conventional Pitot probe, a cone-static probe, and multiple overheat cross-wire anemometry. In addition, schlieren and shadowgraph flow visualization was used to investigate the flow structure at both the injection point and at the downstream data collection point. From these measurements, mass flux component turbulence intensities of 8% to 10% were seen. The total temperature fluctuation was shown to be 6%, which was higher than expected for this adiabatic case. It was also determined that the incompressible component of the Reynolds shear stress accounted for 75% of the total Reynolds shear stress. Another important observation was that the density fluctuation turbulence intensity peaked near the freestream edge of the mixing layer. The turbulent dissipation of kinetic energy was most likely the cause of this peak

Characterization of a Laser-Generated Perturbation in High-Speed Flow for Receptivity Studies

A better understanding of receptivity can contribute to the development of an amplitude-based method of transition prediction. This type of prediction model would incorporate more physics than the semi-empirical methods, which are widely used. The experimental study of receptivity requires a characterization of the external disturbances and a study of their effect on the boundary layer instabilities. Characterization measurements for a laser-generated perturbation were made in two different wind tunnels. These measurements were made with hot-wire probes, optical techniques, and pressure transducer probes. Existing methods all have their limitations, so better measurements will require the development of new instrumentation. Nevertheless, the freestream laser-generated perturbation has been shown to be about 6 mm in diameter at a static density of about 0.045 kg/cubic m. The amplitude of the perturbation is large, which may be unsuitable for the study of linear growth

Experimental techniques for turbulent Taylor–Couette flow and Rayleigh–Bénard convection

Taylor–Couette (TC) flow and Rayleigh–B´enard (RB) convection are two\ud systems in hydrodynamics, which have been widely used to investigate\ud the primary instabilities, pattern formation, and transitions from laminar to\ud turbulent flow. These two systems are known to have an elegant mathematical\ud similarity. Both TC and RB flows are closed systems, i.e. the total energy\ud dissipation rate exactly follows from the global energy balances. From an\ud experimental point of view, the inherent simple geometry and symmetry in these\ud two systems permits the construction of high precision experimental setups.\ud These systems allowfor quantitative measurements of many different variables,\ud and provide a rich source of data to test theories and numerical simulations.\ud We review the various experimental techniques in these two systems in fully\ud developed turbulent states