Draft:Ehsan Roohi

Ehsan Roohi (born in Mashhad, Iran, in July 1982) is a research fellow at the School of Medicine at the University of Maryland. Since January 2024, he has been a lecturer at John Hopkins University. He has a Ph.D. in aerospace engineering. He was a full Professor at the Ferdowsi University of Mashhad and Xi'an Jiaotong University. Based on his research activities, Ehsan Roohi won the Distinguished Young Researcher in Mechanical Engineering award in 2019 in Iran, given by Academy of Sciences of Iran.

Career and research
Ehsan Roohi mainly works on novel and intelligent collision models in the direct simulation Monte Carlo (DSMC) technique framework to make the rarefied flow simulations more accurate and less time-consuming. The collision process is the most sophisticated part of DSMC, which is treated probabilistically. He has demonstrated the shortcomings of conventional collision models and has been developing innovative intermolecular collision paradigms in the framework of the DSMC. In 2015, he improved the "Simplified Bernoulli" trial (SBT) collision model by introducing an intelligent version, and he was the lead developer of a new collision model called the "Generalized Bernoulli" trial (GBT) scheme in 2018. In 2022, he developed another model, the "Symmetrized and Simplified Bernoulli" trial (SSBT) scheme, that has improved performance compared to previous ones. In the same year, Stefan Stefanov and he suggested a hybrid collision scheme on transient adaptive subcells to treat various types of rarefied gas flows at the hypersonic regime.

Contribution to the scientific community
Ehsan Roohi has published more than 129 journal papers and has an h-index of 35 with more than 3414 total citations and performed over 587 verified reviews. He has been Associate Editor of the ASME Journal of Fluid Engineering since 2022 and Associate Editor of the International Journal of Modern Physics C since 2023. He and Yonghao Zhang were the Guest Editors in Physics of Fluids in 2020-2021 for a special issue on "Advances in micro/nano fluid flows: In Memory of Professor Jason Reese". As of January 2024, he is the Guest Editor in Fluids for a special issue on "Rarefied Gas Flows: From Micro-Nano Scale to Hypersonic Regime". He is among the 1% of highly cited researchers in ESI since 2021. Ehsan Roohi has published three textbooks, Gas Dynamics, Fluid Mechanics at Micro and Nano Scales , and Rarefied Gas Dynamics and Direct Simulation Monte Carlo.