koala logs

When dealing with abrupt curves (against the airflow) such as our legs, laminar flow is a bad thing. Laminar flow doesn't "cling" well around abrupt curves and separate much earlier than turbulent flow. Early flow separation results to bigger and more energetic turbulent wake. More energy lost.

Vortex generators break the laminar flow into thin layer of turbulent flow that clings better around abrupt curves and results to a smaller, less energetic turbulent wake - less energy lost from drag. While vortex generators and the turbulent airflow also creates drag and losses, the drag would have been higher if you allowed the the flow to separate early.

The dimples in a golf ball is a form of vortex generator to break the laminar flow around the ball and reduce drag. Most airplanes don't need vortex generators because their wing and body shapes present low amount of curvature against the flow and also because the much larger distance the air has to flow around the airplane body and the much higher speeds involved will easily break the laminar flow into a turbulent layer. Some planes use vortex generators but not to reduce drag but to reduce take off and landing speeds. Vortex generators actually increase drag on a plane but does the opposite on our bikes! This is why on airplanes, maximizing areas of laminar flow is better. Still on some planes like gliders because of the narrow wings and low speeds, can present a more abrupt curve against the airflow, use a more discreet version of vortex generator (that looks like a regular electrician's tape but in a zig zag shape) to help air flow around the wings better. Welcome to the complicated world of aerodynamics!

You can put zig zag tape around your bike to try to reduce some drag...But you'll probably need access to wind tunnel with instrumentation to find where to put them that gives best results.