Hydrodynamic analysis of different thumb positions in swimming

The aim of the present study was to analyze the hydrodynamiccharacteristics of a true model of a swimmer hand with thethumb in different positions using numerical simulationtechniques. a three-dimensional domain was created to simulatethe fluid flow around three models of a swimmer hand, with thethumb in different positions: thumb fully abducted, partiallyabducted, and adducted. these three hand models were obtainedthrough computerized tomography scans of an olympic swimmerhand. steady-state computational fluid dynamics analyseswere performed using the fluent® code. the forces estimated ineach of the three hand models were decomposed into drag andlift coefficients. angles of attack of hand models of 0؛, 45؛ and90؛, with a sweep back angle of 0؛ were used for the calculations.the results showed that the position with the thumb adductedpresented slightly higher values of drag coefficient comparedwith thumb abducted positions. moreover, the positionwith the thumb fully abducted allowed increasing the lift coefficientof the hand at angles of attack of 0؛ and 45؛. these resultssuggested that, for hand models in which the lift force can playan important role, the abduction of the thumb may be better,whereas at higher angles of attack, in which the drag force isdominant, the adduction of the thumb may be preferable.