This project provides a python library to model the viscous effects for thin boundary layers using the integral boundary layer method. Check out the documentation <https://ddmarshall.github.io/IBL/index.html>__ for more info.
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Currently there are a few concrete models to use.
One is Thwaites' method [Thwaites1949]_, which is a single equation model for laminar boundary layers.
Given an edge velocity distribution, u_e, points along the boundary layer edge, s, and initial momentum thickness, delta_m0, the class will calculate the boundary layer properties.
These properties can then be queried at any point along the body.
For example:
.. code-block:: python
from ibl.thwaites_method import ThwaitesMethodNonlinear
# Configure edge information
u_e = ... # edge velocity profile
s = ... # arc-length distance from stagnation point
rho_inf = ... # reference density
nu_inf = ... # reference kinematic viscosity
# Calculate the initial coditions
delta_m0 = ... # initial momentum thickness
# Construct IBL model
tm = ThwaitesMethodNonlinear(U_e=u_e)
tm.initial_delta_m = delta_m0
rtn = tm.solve(x0=s[0], x_end=s[-1])
# Obtain results
if not rtn.success:
print("Could not get solution for Thwaites method: " + rtn.message)
else
tau_wall = tm.tau_w(s, rho_inf)Similarly for a turbulent boundary layer, Head's method [Head1958]_ can be used to calculate the properties for a turbulent boundary layer.
In addition to the initial momentum thickness, the initial displacement shape factor, shape_d0, is needed to initialize the model.
Otherwise, the interface is the same as for Thwaites' method:
.. code-block:: python
from ibl.head_method import HeadMethod
# Configure edge information
u_e = ... # edge velocity profile
s = ... # arc-length distance from stagnation point
rho_inf = ... # reference density
nu_inf = ... # reference kinematic viscosity
# Calculate the initial coditions
delta_m0 = ... # initial momentum thickness
shape_d0 = ... # initial displacement shape factor
# Construct IBL model
hm = ThwaitesMethodNonlinear(U_e=U_e)
hm.initial_delta_m = delta_m0
hm.initial_shape_d = shape_d0
rtn = hm.solve(x0=s[0], x_end=s[-1])
# Obtain results
if not rtn.success:
print("Could not get solution for Thwaites method: " + rtn.message)
else
tau_wall = hm.tau_w(s, rho_inf).. [Thwaites1949] Thwaites, B. “Approximate Calculation of the Laminar Boundary Layer.” The Aeronautical Journal, Vol. 1, No. 3, 1949, pp. 245–280. .. [Head1958] Head, M. R. Entrainment in the Turbulent Boundary Layer. Publication 3152. Ministry of Aviation, Aeronautical Research Council, 1958.
The main contributors to this project are:
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License <license.rst>__ along with this program. If not, see http://www.gnu.org/licenses/.