**4. Conclusion**

A detailed review with regard to passive control methods affecting the flow especially at low Reynolds numbers was presented in this chapter. The main purpose of this study is to clarify the passive control techniques for UAVs and MAVs operating at low Reynolds numbers. Besides the explanation of those techniques, especially three passive flow methods at low Reynolds numbers have been highlighted with their results as follows:


the bubble size to be reduced. Thus, better aerodynamic performance with the increasing of lift coefficient has been obtained.

Consequently, this detailed chapter will present a comprehensive, practical, effective roadmap for the aerodynamic researchers especially interested in the flow control techniques over wind turbine blade or MAV applications operating at low Reynolds number regimes.
