An energized mass approach for drag evaluation
Development and testing of a drag evaluation method for bodies moving with constant velocity
L. Jou Ferrer (TU Delft - Aerospace Engineering)
A Sciacchitano – Mentor (TU Delft - Aerodynamics)
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Abstract
In speed sports, the result of a competition might be decided by a very small time difference, so reducing the drag coefficient is a priority. This work introduces a new method to calculate the drag of a transiting object that moves with a constant velocity. It is based on the concept of the energized mass and its only input is raw PIV images obtained with one camera. The energized mass refers to a measure of the normalised kinetic energy of all the fluid that is affected by the movement of the body.
The method was tested on five different experimental cases, pertaining to three different models: a sphere, a cyclist and a skater. The wake was first studied by examining PIV velocity fields, and the energized mass method results were compared to those from a momentum balance approach. The method was found to overestimate the drag of all objects.