Drag of a Disk in Laminar Flow and Flat-Plate Theory Submitted by: Jeffrey Fontenot
Given A disk of nominal thickness is submerged parallel to the flow in a fluid of constant velocity of U
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Assumptions Steady laminar flow fully developed no slip boundary conditions constant temperature constant viscosity constant position of disk constant velocity smooth surfaces disk thickness is negligible
Find An approximate equation to find the drag on a disk in a parallel constant laminar flow
Calculations We start by finding the Reynolds number U is the velocity D is the diameter
Calculations con’t Next we find the drag coefficient which is based on the Reynolds number, this is an approximation given in Eq. 7.27 of the book
Calculations con’t The next step is to find the drag of one side and is given as
We can apply this equation to any dimensions or fluids Calculations con’t This can be expanded to find the total drag of the disk in the following equation We can apply this equation to any dimensions or fluids
Biomed Application This type of equation could be applied to anything that would be inserted into the cardio-vascular system. Some examples consist of stints, needles, or pacemaker leads.
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