I need help with the coding of the simulation:

i have a picture of the reffered code untouched. i tried adjusting it but i always get a plain or ugly plot. eta

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seems to be all

$0$

$\text{'}$

s which i do not understand why. i need a code that can do the simulation and calculate the phase speed,

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and make a Hovmoller diagram but if you do not have time for that its fair

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$$pls help me im so lost.