\"This research concludes that the downwash region of a rotary-wing unmanned aerial vehicle (UAV) does not produce pressure variations substantial enough to cause significant changes in density-based gas concentration measurements. US regulations evaluate gas concentration as a function of gas density, and accurate concentration measurements are critical for protecting health and safety, which means evaluation of actual downwash effects on measured gas concentration is essential.
During experimentation, the UAV was fixed to a stand in a sealed chamber filled with NOx (NO and NO2) of constant concentration. The UAV rotors ran at hovering speeds, and gas concentrations were measured at various locations around the UAV. NOx was chosen due to intended US regulations on surface mine blasting NOx emissions, though the results should be applicable to most emissions of interest that are monitored by a UAV system. All variables other than the presence of downwash were held constant or accounted for, so the only source of concentration variation would have been caused by pressure changes in the downwash region. No significant variations were observed, providing evidence that downwash pressure variations are not substantial enough to alter density-based gas concentration measurements.
Numerous researchers have suggested that downwash may affect gas concentration measurements, though no researcher has previously isolated and defined the effect. This dissertation’s findings allow researchers to safely assume this source of previously undefined error is statistically negligible, provided the UAV and gas sampling point are located entirely within the gas cloud and the downwash region has stabilized\"--Abstract, p. iii
","abstract_html":"<p>"This research concludes that the downwash region of a rotary-wing unmanned aerial vehicle (UAV) does not produce pressure variations substantial enough to cause significant changes in density-based gas concentration measurements. US regulations evaluate gas concentration as a function of gas density, and accurate concentration measurements are critical for protecting health and safety, which means evaluation of actual downwash effects on measured gas concentration is essential.</p> <p>During experimentation, the UAV was fixed to a stand in a sealed chamber filled with NOx (NO and NO<sub>2</sub>) of constant concentration. The UAV rotors ran at hovering speeds, and gas concentrations were measured at various locations around the UAV. NOx was chosen due to intended US regulations on surface mine blasting NOx emissions, though the results should be applicable to most emissions of interest that are monitored by a UAV system. All variables other than the presence of downwash were held constant or accounted for, so the only source of concentration variation would have been caused by pressure changes in the downwash region. No significant variations were observed, providing evidence that downwash pressure variations are not substantial enough to alter density-based gas concentration measurements.</p> <p>Numerous researchers have suggested that downwash may affect gas concentration measurements, though no researcher has previously isolated and defined the effect. This dissertation’s findings allow researchers to safely assume this source of previously undefined error is statistically negligible, provided the UAV and gas sampling point are located entirely within the gas cloud and the downwash region has stabilized"--Abstract, p. iii</p>","abstract_has_math":false,"creators":["Brinkman, Jacob Lane"],"institution":"Missouri University of Science and Technology","degree_name":"Ph. D. in Explosives Engineering","degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":null,"date_issued":"","date_published":null,"updated_at":"2026-07-24T03:18:18Z","subjects":["blasting","downwash","gas emissions","gas monitor","UAV","Engineering","Explosives Engineering","Mining Engineering"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarsmine.mst.edu/doctoral_dissertations/3254","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Brinkman, Jacob Lane"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:type","label":"Dc Type","values":["Dissertation - Open Access"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph. D. in Explosives Engineering"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Missouri University of Science and Technology"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["blasting","downwash","gas emissions","gas monitor","UAV","Engineering","Explosives Engineering","Mining Engineering"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarsmine.mst.edu/doctoral_dissertations/3254"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["\"This research concludes that the downwash region of a rotary-wing unmanned aerial vehicle (UAV) does not produce pressure variations substantial enough to cause significant changes in density-based gas concentration measurements. US regulations evaluate gas concentration as a function of gas density, and accurate concentration measurements are critical for protecting health and safety, which means evaluation of actual downwash effects on measured gas concentration is essential.
During experimentation, the UAV was fixed to a stand in a sealed chamber filled with NOx (NO and NO2) of constant concentration. The UAV rotors ran at hovering speeds, and gas concentrations were measured at various locations around the UAV. NOx was chosen due to intended US regulations on surface mine blasting NOx emissions, though the results should be applicable to most emissions of interest that are monitored by a UAV system. All variables other than the presence of downwash were held constant or accounted for, so the only source of concentration variation would have been caused by pressure changes in the downwash region. No significant variations were observed, providing evidence that downwash pressure variations are not substantial enough to alter density-based gas concentration measurements.
Numerous researchers have suggested that downwash may affect gas concentration measurements, though no researcher has previously isolated and defined the effect. This dissertation’s findings allow researchers to safely assume this source of previously undefined error is statistically negligible, provided the UAV and gas sampling point are located entirely within the gas cloud and the downwash region has stabilized\"--Abstract, p. iii
"]},{"key":"dc:title","label":"Title","values":["Effects of Downwash when Measuring Gas Concentration with UAV-Mounted Gas Sensors"]}]}],"canonical_facts":{"dc:creator":["Brinkman, Jacob Lane"],"dc:description.abstract":["\"This research concludes that the downwash region of a rotary-wing unmanned aerial vehicle (UAV) does not produce pressure variations substantial enough to cause significant changes in density-based gas concentration measurements. US regulations evaluate gas concentration as a function of gas density, and accurate concentration measurements are critical for protecting health and safety, which means evaluation of actual downwash effects on measured gas concentration is essential.
During experimentation, the UAV was fixed to a stand in a sealed chamber filled with NOx (NO and NO2) of constant concentration. The UAV rotors ran at hovering speeds, and gas concentrations were measured at various locations around the UAV. NOx was chosen due to intended US regulations on surface mine blasting NOx emissions, though the results should be applicable to most emissions of interest that are monitored by a UAV system. All variables other than the presence of downwash were held constant or accounted for, so the only source of concentration variation would have been caused by pressure changes in the downwash region. No significant variations were observed, providing evidence that downwash pressure variations are not substantial enough to alter density-based gas concentration measurements.
Numerous researchers have suggested that downwash may affect gas concentration measurements, though no researcher has previously isolated and defined the effect. This dissertation’s findings allow researchers to safely assume this source of previously undefined error is statistically negligible, provided the UAV and gas sampling point are located entirely within the gas cloud and the downwash region has stabilized\"--Abstract, p. iii
"],"dc:identifier":["https://scholarsmine.mst.edu/doctoral_dissertations/3254"],"dc:subject":["blasting","downwash","gas emissions","gas monitor","UAV","Engineering","Explosives Engineering","Mining Engineering"],"dc:title":["Effects of Downwash when Measuring Gas Concentration with UAV-Mounted Gas Sensors"],"dc:type":["Dissertation - Open Access"],"thesis:degree_name":["Ph. D. in Explosives Engineering"],"thesis:institution_name":["Missouri University of Science and Technology"]},"updated_at":"2026-07-24T03:18:18Z"}