Laminar-turbulent transition of hypersonic boundary layers is believed to be sensitive to particulates that exist in the atmosphere. In order to better understand their role in the transition process, it is necessary to know their number concentration and size distribution at relevant altitudes. This paper reports on preliminary in-situ measurements of particulate number concentrations and size distributions that were performed during two high-altitude balloon flights over southern Minnesota. Vertical profiles of the particulate number concentration for 19 size classes within the 0.2 to 50 µm diameter size range are presented up to an altitude of 34 km. Particulate size distributions are presented above 22 km and up to an altitude of 34 km.
|Original language||English (US)|
|Title of host publication||AIAA Scitech 2020 Forum|
|Publisher||American Institute of Aeronautics and Astronautics Inc, AIAA|
|State||Published - 2020|
|Event||AIAA Scitech Forum, 2020 - Orlando, United States|
Duration: Jan 6 2020 → Jan 10 2020
|Name||AIAA Scitech 2020 Forum|
|Conference||AIAA Scitech Forum, 2020|
|Period||1/6/20 → 1/10/20|
Bibliographical noteFunding Information:
This work was sponsored by the Air Force Office of Scientific Research (AFOSR) under grant FA9550-18-1-0009. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the AFOSR or the U.S. Government.