To determine the primary wave propagation direction from a sequence of eta (surface elevation), u (horizontal velocity), and v (vertical velocity) data frames

[hadley lau]

Dear funwave-tvd users,

I hope this message finds you well.

I am currently analyzing the directional distribution of wave energy to determine the primary wave propagation direction. In this process, I divide the complete directional range (0°–360°) into M equal intervals, each with a width of Δθ = 360°/M. For each time step n, I calculate the instantaneous direction θₙ from the velocity components and ensure it falls within the range [0°, 360°). If θₙ lies within the i-th directional interval (θᵢ, θᵢ + Δθ), I add the corresponding instantaneous squared wave height eₙ² to the total energy sum for that interval: Eᵢ ← Eᵢ + eₙ². After processing all time steps, the interval with the maximum cumulative energy Eᵢ corresponds to the dominant wave propagation direction. I approximate this direction as: θₘₐᵢₙ ≈ θᵢₘₐₓ + Δθ/2, where iₘₐₓ = arg maxᵢ Eᵢ.   The image below is an example of the distribution I calculated.  

I would greatly appreciate it if you could review this methodology and let me know if it is correct. If you have any suggestions for improvement, I would be grateful to hear them.

Thank you for your time and assistance.

Best regards,

Hadley lau

An example of the distribution I calculated.