FTBS

Author: dauzickaite

src/linear_advection.py

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+# Solve linear advection equation 
+
+### Try FTBS
+
+from  math import *
+import numpy as np
+import pylab
+
+# Divide space into equal intervals
+npoints = 40 # no of points
+
+points = np.linspace(0, 1, npoints)
+
+# Divide time into time steps
+ntime = 100 # no of time steps
+
+# Wind 
+# Courant number
+c = 0.2
+d = 1 - c
+
+# Initial conditions (dar reikia paziureti, kaip efektyviau padaryti)
+# Pabandyti ir kitas pradines salygas
+phi_new = []
+for x in points:
+    if x <= 0.5:
+        phi_new.append(0.5 * (1 - cos(4 * pi * x)))
+    else:
+        phi_new.append(0)
+
+phi_new = np.array(phi_new)
+pylab.plot(points, phi_new)
+
+for tstep in range(ntime): # ntime
+    #phi_new = np.array(phi_new)
+    #pylab.plot(point, phi_new)
+    phi_old = phi_new[:]
+    phi_new = []
+    for j in range(npoints):
+        phi_new.append(d * phi_old[j] + c * phi_old[j-1])
+        
+phi_new = np.array(phi_new)
+pylab.plot(points, phi_new)
+
+# Jeigu tasku skaicius ir c kitoks, kazkuriuo metu pabaiga pradeda
+# kilti ir tada persinesa visa banga i sona. Kodel ir ar susije su krastais