Need a hand with the Morison Equation with $k$ giving me a headache.

I'm following a video online trying to calculate the force on a structure I am designing for work. I try to follow videos using their numbers to ensure I get the formulae right in excel, but I can't seem to understand why my $k$ value, even though it's the same, gives me a massive number.

The lady in the video summarizes the equation in red. I broke down each part such that my excel function does not become too complicated.

Morisons Equation (after integration):

$$ \rho C_M\frac{\pi D^2}{4}\frac{2\pi H}{T^2}\frac 1k 1-e^{-kd}\sin(kx-\sigma t) $$

Waveform number:

$$ k=\frac{2\pi}{\lambda}=\frac{2\pi}{224.7}=0.279 $$

Breaking down values as follows:

ITEM Result
$\rho C_M$ 2050
$\frac{\pi D^2}{4}$ 0.7853
$\frac{2\pi H}{T^2}$ 13.1594
$\frac 1k$ 35.76212
$1-e^{-kd}$ 0.027575

My result, ignoring the trig function, equals 20894.13, which is not her 62.2 value.

Any advice?

  • 1
    $\begingroup$ There are brackets around $(1-e^{-k d})$, and also $k=0.028$ . With these corrections we have 62190.7N approximately 62.2kN as expected. $\endgroup$ – Alex Trounev Jun 15 at 11:32

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