### Add some basic info about the planetary hydro scheme and EoS

parent b79dbe1c
 .. Equation of State .. Equations of State Loic Hausammann, 6th April 2018 Jacob Kegerreis, 3rd February 2019 .. _equation_of_state: Equation of State ================= Equations of State ================== Currently (if the documentation was well updated), we have two different equation of states implemented: ideal gas and isothermal. They describe the relations between our main thermodynamical variables: the internal energy (\$$u\$$), the density (\$$\\rho\$$), the entropy (\$$A\$$) and the pressure (\$$P\$$). Currently (if the documentation was well updated), we have two different gas equations of state (EoS) implemented: ideal and isothermal; as well as a variety of EoS for "planetary" materials. The EoS describe the relations between our main thermodynamical variables: the internal energy (\$$u\$$), the density (\$$\\rho\$$), the entropy (\$$A\$$) and the pressure (\$$P\$$). Equations --------- Gas EoS ------- In the following section, the variables not yet defined are: \$$\\gamma\$$ for the adiabatic index and \$$c_s \$$ for the speed of sound. ... ... @@ -37,12 +39,55 @@ the adiabatic index and \$$c_s \$$ for the speed of sound. "\$$c_s\$$", "", "\$$\\sqrt{ u \\gamma \\left( \\gamma - 1 \\right) } \$$", "" Planetary EoS ------------- Configuring SWIFT with the --with-equation-of-state=planetary and --with-hydro=planetary options enables the use of multiple EoS. Every SPH particle then requires and carries the additional MaterialID flag from the initial conditions file. This flag indicates the particle's material and which EoS it should use. So far, we have implemented several Tillotson, SESAME, and Hubbard \& MacFarlane (1980) materials, with more on their way. The material's ID is set by a base type ID (multiplied by 100), plus a minor type: + Tillotson (Melosh, 2007): 1 + Iron: 100 + Granite: 101 + Water: 102 + Hubbard \& MacFarlane (1980): 2 + Hydrogen-helium atmosphere: 200 + Ice H20-CH4-NH3 mix: 201 + Rock SiO2-MgO-FeS-FeO mix: 202 + SESAME (and similar): 3 + Iron (2140): 300 + Basalt (7530): 301 + Water (7154): 302 + Senft \& Stewart (2008) water (in a SESAME-style table): 303 Unlike the EoS for an ideal or isothermal gas, these more complicated materials do not always include transformations between the internal energy, temperature, and entropy. At the moment, we have only implemented \$$P(\\rho, u)\$$ and \$$c_s(\\rho, u)\$$. This is sufficient for the simple :ref:planetary_sph hydrodynamics scheme, but makes these materials currently incompatible with other entropy-based schemes. The Tillotson sound speed was derived using \$$c_s^2 = \\left. \\dfrac{\\partial P}{\\partial \\rho} \\right|_S \$$ as described in Kegerreis et al. (2019). The tables for the HM80 and SESAME-style EoS can be downloaded from http://astro.dur.ac.uk/~cklv53/uranus_1e6/ . How to Implement a New Equation of State ---------------------------------------- See :ref:new_option for a full list of required changes. You will need to provide a equation_of_state.h file containing: the You will need to provide an equation_of_state.h file containing: the definition of eos_parameters, IO functions and transformations between the different variables: \$$u(\\rho, A)\$$, \$$u(\\rho, P)\$$, \$$P(\\rho,A)\$$, \$$P(\\rho, u)\$$, \$$A(\\rho, P)\$$, \$$A(\\rho, u)\$$, \$$c_s(\\rho, A)\$$, ... ...
 ... ... @@ -15,6 +15,7 @@ schemes available in SWIFT, as well as how to implement your own. traditional_sph minimal_sph planetary hopkins_sph gizmo adding_your_own ... ...
 .. Planetary SPH Jacob Kegerreis, 3rd February 2019 .. _planetary_sph: Planetary (Density-Energy, Multi-Material) SPH ============================================== .. toctree:: :maxdepth: 2 :hidden: :caption: Contents: This scheme is the same as the Minimal SPH scheme but also allows multiple materials, meaning that different SPH particles can be assigned different :ref:equation_of_state (EoS). To use the planetary scheme and the corresponding planetary EoS, use .. code-block:: bash ./configure --with-hydro=planetary --with-equation-of-state=planetary Every SPH particle then requires and carries the additional MaterialID flag from the initial conditions file. This flag indicates the particle's material and which EoS it should use. \ No newline at end of file
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!