Daan Crommelin investigates uncertainties in numerical simulations of complex dynamical systems. All kinds of uncertain factors play a role in simulations of the time evolution of complex systems, such as atmosphere and climate. These uncertainties are connected with, among other things, the non-linear character of such systems, and with the (unavoidable) limited resolution of simulations as a result of finite computing power. Crommelin studies how uncertainties can be represented in numerical simulations through stochastic processes. This work is primarily aimed at application in models for atmospheric and ocean currents. Crommelin also performs research on methods for efficiently simulating extreme events in dynamical systems with uncertainties, an area of study that has applications in the field of energy networks, for example.

Crommelin has been a researcher at the Centrum Wiskunde & Informatica (CWI), the national research institute for mathematics and computer science in Amsterdam, since 2006. He was appointed head of the Scientific Computing research group at CWI in 2013. From 2003 to 2006, Crommelin worked as a postdoctoral researcher and assistant professor at New York University's Courant Institute of Mathematical Sciences in the US. Crommelin received a Vidi grant from the Netherlands Organisation for Scientific Research (NWO) in 2012 for his research project on ‘Stochastic Models for Unresolved Scales in Geophysical Flows’. Crommelin is a member of the editorial board of the interdisciplinary journal Multiscale Modeling and Simulation published by the Society for Industrial and Applied Mathematics (SIAM).