def get_bed_slope(self, eta, domain_length):
bed_slope = tools.central_difference(eta, self.dxbar * domain_length)
bed_slope[-2] = (eta[-3] - eta[-2]) / (self.dxbar * domain_length)
bed_slope[-1] = (eta[-2] - eta[-1]) / (self.dxbar * domain_length)
return bed_slope
def advance_one_timestep(self):
if self._friction == "Manning":
Cf = (1/self._alpha_r**2) * (self._kc / self._H)**(1./3)
if self._friction == "Chezy":
Cf = self._Cf
self._tau = Cf * (self._qw / self._H)**2 / (self._g * self._R * self._D90)
self._load = self._phi * self._tau - self._tau_c
self._load[self._load <= 0] = 0
self._load[self._load > 0] = self._alpha_t * self._load[self._load > 0]**self._n
self._qb = self._load * self._D90 * sqrt(self._R * self._g * self._D90)
_qtf = self._Gtf / (self._B * (1+self._R) * self._If * self._sec_to_year)
self._dq = tools.central_difference(self._qb,
self._dx,
alpha = self._alpha_u,
left_boundary = _qtf)
self._eta = (self._eta +
(self._dt * self._sec_to_year / (1-self._porosity)) * self._If * self._dq)
def advance_one_timestep(self):
# Slope
self.Sl = tools.central_difference(self.eta, self.dx)
# Water depth
if self.friction == 'Manning':
self.H = (self.Qf**2 * self._kc**(1./3) / \
(self.alpha_r**2 * self.channel_width**2 * self.g * self.Sl))**(3./10.)
if self.friction == 'Chezy':
self.H = (self.Qf**2 * self.Cf / (self.g * self.channel_width**2 * self.Sl))**(1./3)
# Shear stress
self.tau = self.H * self.Sl / (self._R * self._D)
# Bed sediment load
self.load = self.phi * self.tau - self.tau_c
self.load[self.load <= 0] = 0
self.load[self.load > 0] = self.alpha_t * self.load[self.load > 0]**self.nt
self.qb = self.load * self._D * sqrt(self._R * self.g * self._D)
# Spatial derivative of sediment load
qtf = self.Gtf / (self.channel_width * (1+self._R) * self.If * self.sec_to_year)
self.dq = tools.central_difference(self.qb,
self.dx,
alpha = self.alpha_u,
left_boundary = qtf)
self.dq[-1] = 0
self.eta = self.eta - self.subs1 +\
(self.dt * self.sec_to_year / (1-self.porosity)) * self.If * self.dq * self.subs2
