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Switched fft to psd

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This commit is contained in:
Edgar P. Burkhart 2022-03-07 12:25:38 +01:00
parent d945770453
commit fa2e30deec
Signed by: edpibu
GPG key ID: 9833D3C5A25BD227
2 changed files with 14 additions and 8 deletions
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2
swash/config.ini
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@ -18,7 +18,9 @@ mpi=4
[post]
inp=inp_post
case=sws_spec_buoy.npz
out=out_post
#nperseg=1024
dt=0.25
x0=-1000
t0=180

20
swash/processing/post.py
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@ -26,7 +26,7 @@ inp = pathlib.Path(config.get("post", "inp"))
root = pathlib.Path(config.get("swash", "out"))
log.info(f"Reading bathymetry from '{inp}'")
data = np.load(inp.joinpath("sws.npz"))
data = np.load(inp.joinpath(config.get("post", "case")))
x, t = data["x"], data["t"]
# Cospectral calculations
@ -36,14 +36,15 @@ t0 = config.getfloat("post", "t0")
arg_t0 = np.abs(t - t0).argmin()
dt = config.getfloat("post", "dt")
f = 1 / dt
nperseg = config.getint("post", "nperseg", fallback=None)
log.info(f"Computing reflection coefficient at x={x0}")
eta = data["watl"][t > t0, arg_x0]
u = data["vel"][t > t0, 0, arg_x0]
phi_eta = np.abs(sgl.csd(eta, eta, f))
phi_u = np.abs(sgl.csd(u, u, f))
phi_eta_u = np.abs(sgl.csd(eta, u, f))
phi_eta = np.abs(sgl.welch(eta, f, nperseg=nperseg))
phi_u = np.abs(sgl.welch(u, f, nperseg=nperseg))
phi_eta_u = np.abs(sgl.csd(eta, u, f, nperseg=nperseg))
R = np.sqrt(
(phi_eta[1] + phi_u[1] - 2 * phi_eta_u[1])
@ -72,16 +73,19 @@ fig_r, ax_r = plt.subplots()
ax_fft = ax_r.twinx()
ax_fft.plot(
fft.rfftfreq(eta.size, dt),
np.abs(fft.rfft(eta)),
*sgl.welch(eta, 1/dt, nperseg=nperseg),
lw=1,
c="k",
alpha=0.2,
label="PSD",
)
ax_r.plot(phi_eta[0], R, marker="+")
ax_r.plot(phi_eta[0], R, marker="+", label="R")
ax_r.set(xlim=(0, 0.3), ylim=(0, 1), xlabel="f (Hz)", ylabel="R")
ax_fft.set(ylim=0, ylabel="FFT")
ax_fft.set(ylim=0, ylabel="PSD (m²/Hz)")
ax_r.grid()
ax_r.legend(loc="upper left")
ax_fft.legend(loc="upper right")
fig_r.tight_layout()
fig_x, ax_x = plt.subplots()
ax_x.plot(data["x"], -data["botl"], color="k")