Skip to content
GitLab
Menu
Projects
Groups
Snippets
Help
Help
Support
Community forum
Keyboard shortcuts
?
Submit feedback
Sign in
Toggle navigation
Menu
Open sidebar
KiT-RT
KiT-RT
Commits
2fbcd7a2
Commit
2fbcd7a2
authored
Feb 26, 2021
by
Tianbai Xiao
Browse files
Finish theory part
parent
11df4f4c
Pipeline
#138043
canceled with stage
Changes
1
Pipelines
1
Hide whitespace changes
Inline
Side-by-side
doc/physics.rst
View file @
2fbcd7a2
...
...
@@ -134,7 +134,7 @@ over all angles to give
.. math::
\frac{1}{v} \partial_{t} u+\nabla_{x} \cdot\langle\Omega m \psi\rangle=\langle m \mathcal{C}(\psi)\rangle
\frac{1}{v} \partial_{t} u+\nabla_{x} \cdot\langle\Omega m \psi\rangle=\langle m \mathcal{C}(\psi)\rangle
.
The system above is not closed; a recipe, or closure, must be prescribed to express
unknown quantities in terms of the given moments. Often this is done via an
...
...
@@ -142,7 +142,7 @@ approximation for :math:`\psi` that depends on :math:`u`,
.. math::
\psi(x, \Omega, t) \simeq \mathcal{E}(u(x, t))(\Omega)
\psi(x, \Omega, t) \simeq \mathcal{E}(u(x, t))(\Omega)
.
A general strategy for prescribing a closure is to
use the solution of a constrained optimization problem
...
...
@@ -151,8 +151,7 @@ use the solution of a constrained optimization problem
:label: closure
\min_{g \in \operatorname{Dom}(\mathcal{H})} & \mathcal{H}(g) \\
\quad \text { s.t. } & \langle\mathbf{m} g\rangle=\langle\mathbf{m} \psi\rangle=u
\end{array}
\quad \text { s.t. } & \langle\mathbf{m} g\rangle=\langle\mathbf{m} \psi\rangle=u,
where :math:`\mathcal H(g)=\langle \eta(g) \rangle` and $\eta: \mathbb R \rightarrow \mathbb R$
is a convex function that is related to
...
...
@@ -161,21 +160,27 @@ Bose-Einstein statistics
.. math::
\eta(g)=\frac{2 k \nu^{2}}{c^{3}}\left[n_{g} \log \left(n_{g}\right)-\left(n_{g}+1\right) \log \left(n_{g}+1\right)\right]
\eta(g)=\frac{2 k \nu^{2}}{v^{3}}\left[n_{g} \log \left(n_{g}\right)-\left(n_{g}+1\right) \log \left(n_{g}+1\right)\right],
where :math:`n_g` is the occupation number associated with g,
.. math::
n_{g}:=\frac{v^{2}}{2 h \nu^{3}} g.
The solution of :eq:`closure` is expressed in terms of the Legendre dual
.. math::
\eta_{*}(f)=-\frac{2 k \nu^{2}}{
c
^{3}} \log \left(1-\exp \left(-\frac{h \nu c}{k} f\right)\right)
\eta_{*}(f)=-\frac{2 k \nu^{2}}{
v
^{3}} \log \left(1-\exp \left(-\frac{h \nu c}{k} f\right)\right)
.
Let
.. math::
\mathcal{B}(\boldsymbol{\alpha}):=\eta_{*}^{\prime}\left(\boldsymbol{\alpha}^{T} \mathbf{m}\right)=\frac{2 h \nu^{3}}{
c
^{2}} \frac{1}{\exp \left(-\frac{h \nu c}{k} \boldsymbol{\alpha}^{T} \mathbf{m}\right)-1}
\mathcal{B}(\boldsymbol{\alpha}):=\eta_{*}^{\prime}\left(\boldsymbol{\alpha}^{T} \mathbf{m}\right)=\frac{2 h \nu^{3}}{
v
^{2}} \frac{1}{\exp \left(-\frac{h \nu c}{k} \boldsymbol{\alpha}^{T} \mathbf{m}\right)-1}
,
T
he solution of :eq:`closure` is given by :math:`\mathcal B(\hat \alpha)`, where :math:`\hat \alpha= \hat \alpha(u)` solves the
then t
he solution of :eq:`closure` is given by :math:`\mathcal B(\hat \alpha)`, where :math:`\hat \alpha= \hat \alpha(u)` solves the
dual problem
.. math::
...
...
jannick.wolters
@jm2154
mentioned in commit
f5a65b82
·
Apr 30, 2021
mentioned in commit
f5a65b82
mentioned in commit f5a65b8270637e6400a084d5da9c54a88847f71e
Toggle commit list
Write
Preview
Supports
Markdown
0%
Try again
or
attach a new file
.
Attach a file
Cancel
You are about to add
0
people
to the discussion. Proceed with caution.
Finish editing this message first!
Cancel
Please
register
or
sign in
to comment