Pushing a cylinder through the water with an angular velocity of $\omega$.

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The cylinder diameter and length are $D$ and $L$ respectively and the length from the rotation point to the center of the cylinder is $L_{arm}$.

$F_D = \frac{1}{2} \cdot \rho \cdot C_D \cdot A \cdot v^2 $

But how do I find the drag coefficient?

  • 1
    $\begingroup$ By experiment is a possibility. $\endgroup$
    – Solar Mike
    Nov 1, 2022 at 10:53
  • $\begingroup$ I don't have that possibility $\endgroup$
    – Babar
    Nov 1, 2022 at 10:58

1 Answer 1


There are tables for common shapes, e.g. in my fluid mechanics formulary I find for a long cylinder $C_\text{D}=0.3 \dots 1.3$ depending on the Re-Number.


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