Vortex generators are disclosed herein. An example apparatus includes a housing including a surface. The example apparatus also includes a bimorph actuator disposed in the housing. The bimorph actuator includes a first bimorph beam having a first portion fixed relative to the surface. A blade is rotatably coupled to the bimorph actuator, and the bimorph actuator is to rotate the blade to extend a portion of the blade through the surface to generate a vortex in a fluid flowing past the surface.