Mechanical & Materials Engineering, Department of

 

First Advisor

Carrick Detweiler

Date of this Version

8-2019

Citation

Ashraful Islam. Design and evaluation of sensor housing for atmospheric boundary layer profiling using multirotors. Master's thesis, University of Nebraska-Lincoln, 2019

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfilment of Requirements For the Degree of Master of Science, Major: Mechanical Engineering and Applied Mechanics, Under the Supervision of Professor Carrick Detweiler. Lincoln, Nebraska: August, 2019

Copyright © 2019 Ashraful Islam

Abstract

Traditional configurations for mounting Temperature–Humidity (TH) sensors on multirotor Unmanned Aerial Systems (UASs) often suffer from insufficient radiation shielding, exposure to mixed and turbulent air from propellers, and inconsistent aspiration while situated in the wake of the UAS. Consequently, atmospheric boundary layer profiles that rely on such configurations are bias-prone and unreliable in descent. This thesis describes the evolution of a novel sensor housing design over three iterations. The sensor housing is designed to shield airborne sensors from artificial heat sources and artificial wet-bulbing while pulling air from outside the rotor wash influence. The housing is mounted above the propellers to exploit the rotor-induced pressure deficits that passively induce a high-speed laminar airflow to aspirate the sensor consistently. Our design is modular, accommodates a variety of other sensors, and would be compatible with a wide range of commercially available multirotors. Extensive flight tests conducted at three field campaigns with altitudes up to 500 m Above Ground Level (AGL) show that the housing facilitates reliable measurements of the boundary layer phenomena and is invariant in orientation to the ambient wind, even at high vertical/horizontal speeds (up to 5 m/s) for the UAS. A low standard deviation of TH measurements shows a good agreement between the ascent and descent profiles and proves our unique design is reliable for various UAS missions.

Advisor: Carrick Detweiler

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