Showcase of what the solver can output for a bi-layer surface profile on Japet. Note that here the interface is located around 32 cm. Additional figures may be found in the examples directory.

• python
• git

conda

Copy the project localy using git clone:

git clone [email protected]:cyril.mergny/multiheats.git

then cd to the path of the repositery on you computer and create a venv environment:

cd path_to_multiheats/
python -m venv mheats
source mheats/bin/activate

To install the package then you just need to type:

pip install poetry --upgrade pip
poetry install --with dev

conda env create -f environment.yml

pip install -e .

Make sure to activate the python environment before executing anything:

source mheats/bin/activate

There is an example script that you can run to see what the algorithm ouptut for a pre-defined profile.

cd path_to_multiheats/examples/
python example_1.py

After iterating over all timestep the script should output matplotlib figures.

I suggest first copying the example_1.py file to use it as a template. You can write you own personal modifications directly in the python code of this file.

The albedo, emissivity of the surface, depth array, etc... can be modified in the init method of the Profile class.

nx = 100  # Grid points
xmin, xmax = 0, 2  # depth limits (m)
alb = 0.2  # Albedo
eps = 1.0  # Emissivity
nday = 200  # Nbr of days
step_per_day = int(1e2)  # Points per day
distance = 9.51 * cst.UA  # Distance to sun (m)
period = 79.3 * cst.EARTH_DAY  # Diurnal period (s)

prof = Profile(nx, eps, xmin, xmax, power=3)
# TOP
cond_top = 0.01
rho_top = 917.0
cp_top = 839
# BOTTOM
cond_bot = cond_top / 2
rho_bot = rho_top / 2
cp_bot = cp_top / 2
# Interface
thermal_skin = prof.thermal_skin(cond_top, rho_top, cp_top, period)
interface = 2 * thermal_skin  # (m)

The solver is meant to be working for any type of multi-layered surfaces. The surface material property profiles may be changed directly inside the create_profile.py python script.

For example to change the values of an homegeneous profile, change the arguments cond, rho, cp of the method monolayer_prof() The same can be done for the bilayer profile: change the arguments of the method bilayer_prof(). For any types of other exotic profiles (3 layers, etc...), feel free to write you own method in Profile class.

The solar flux can either be imported from data that you own, or created artificially using a truncated cosinus function.

I would not recommend tweaking with the solvers.py module unless you know what you are doing. Anyway, the top and bottom boundary conditions may be change in the set_flux_BC() method.

def set_flux_BC(self, matrice, source, dt):
    """
    Set boundary conditions for implicit Euler Scheme
    Imposed flux or imposed temperature possible.
    """
    rcoef = dt / self.rho / self.cp
    cond = self.cond

    # Set Boundary conditions
    bc_top = self.solar_flux / cond[0]
    bc_top += self.eps * cst.SIGMA / self.cond[0] * self.temp[0] ** 4
    self.bc_top = bc_top
    bc_bottom = 0
    ...

For example to add a radioactive thermal flux coming from the planet interior change bc_bottom to the flux' value.

The solvers is supposed to work with flux or temperature boundary conditions. Although for the second case some additional modifications may be required to make the solver work.

Just modify or write you own functions in the visualise.py module.

Contributions are welcome:

• Feel free to open an issue for feedback about usability.
• You may fork the project as you wish as long as you cite the original in your research.
• Pull request may be accepted if new features are in the scope of the MultIHeaTS core.

Please keep pull requests focused and don't change multiple things at the same time.

If you use this code or parts of this code in your work, please cite the following article:

Mergny et al. 2023, [Article Submitted] Come back here later for the DOI.

MultIHeaTS is distributed under the terms of the GNU GPL License Version 3. A complete version of the license is available in the COPYING file in this repository. Any contribution made to this project will be licensed under the GNU GPL License Version 3.