  Reduced order modeling has gained considerable attention in recent decades
owing to the advantages offered in reduced computational times and multiple
solutions for parametric problems. The focus of this manuscript is the
application of model order reduction techniques in various engineering and
scientific applications including but not limited to mechanical, naval and
aeronautical engineering. The focus here is kept limited to computational fluid
mechanics and related applications. The advances in the reduced order modeling
with proper orthogonal decomposition and reduced basis method are presented as
well as a brief discussion of dynamic mode decomposition and also some present
advances in the parameter space reduction. Here, an overview of the challenges
faced and possible solutions are presented with examples from various problems.
