@@ -74,7 +74,7 @@ This yields a global error of order :math:`O(\Delta t^4)` with four velocity eva
7474
7575**Sixth-Order Runge-Kutta (RK6) **
7676
77- The six -stage scheme uses non-uniform weights to attain sixth-order accuracy:
77+ The seven -stage scheme uses non-uniform weights to attain global :math: `O( \Delta t^ 6 )` accuracy. This method originates from
7878
7979.. math ::
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@@ -86,34 +86,27 @@ The six-stage scheme uses non-uniform weights to attain sixth-order accuracy:
8686 k_6 = \mathbf {u}\!\bigl (\mathbf {x}_n + \Delta t(-\tfrac {3 }{2 }k_1 + 2 k_2 - \tfrac {1 }{2 }k_3 + k_4 ),\; t_n + \Delta t\bigr ),\\
8787 \mathbf {x}_{n+1 } = \mathbf {x}_n + \Delta t\bigl (\tfrac {1 }{20 }k_1 + \tfrac {1 }{4 }k_4 + \tfrac {1 }{5 }k_5 + \tfrac {1 }{2 }k_6 \bigr ).
8888
89- This scheme incurs a global error of order :math: `O(\Delta t^6 )` with six velocity evaluations.
90-
91-
92- +-------------------+------------------------------------------------------+-------------------------+---------------------------------------------------------------------------------------------------------+
93- | ``output_dir `` | Path to directory for saving results | ``<string> `` | |
94- +-------------------+------------------------------------------------------+-------------------------+---------------------------------------------------------------------------------------------------------+
95- | ``auto_wall `` | Flag for automatic wall detection | ``0 `` | Manually indicate computation bounds. |
96- +-------------------+------------------------------------------------------+-------------------------+---------------------------------------------------------------------------------------------------------+
97- | | | (``1 ``) | Auto detect bounds from input mesh. |
98- +-------------------+------------------------------------------------------+-------------------------+---------------------------------------------------------------------------------------------------------+
99- | ``wall_xrange `` | X-direction wall bounds [xmin, xmax] | ``[<float>, <float>] `` | Dimensionalized coordinates bounds. |
100- +-------------------+------------------------------------------------------+-------------------------+---------------------------------------------------------------------------------------------------------+
101- | ``wall_yrange `` | Y-direction wall bounds [ymin, ymax] | ``[<float>, <float>] `` | |
102- +-------------------+------------------------------------------------------+-------------------------+---------------------------------------------------------------------------------------------------------+
103- | ``wall_zrange `` | Z-direction wall bounds [zmin, zmax] | ``[<float>, <float>] `` | |
104- +-------------------+------------------------------------------------------+-------------------------+---------------------------------------------------------------------------------------------------------+
105- | ``x `` | Number of Lagrangian seed points in X direction | ``<int> `` | |
106- +-------------------+------------------------------------------------------+-------------------------+---------------------------------------------------------------------------------------------------------+
107- | ``y `` | Number of Lagrangian seed points in Y direction | ``<int> `` | |
108- +-------------------+------------------------------------------------------+-------------------------+---------------------------------------------------------------------------------------------------------+
109- | ``z `` | Number of Lagrangian seed points in Z direction | ``<int> `` | |
110- +-------------------+------------------------------------------------------+-------------------------+---------------------------------------------------------------------------------------------------------+
111- | ``T_range `` | Time range [``T_start ``, ``T_end ``] in frames | ``[<float>, <float>] `` | ``T_end `` no larger than ``N_frames ``. |
112- +-------------------+------------------------------------------------------+-------------------------+---------------------------------------------------------------------------------------------------------+
113- | ``dt `` | Time step for particle advection in frames | ``<float> `` | |
114- +===================+======================================================+=========================+=========================================================================================================+
115- | ``physical_dt `` | Physical time step between two input frames | ``<float> `` | Perform physical advection. |
116- +-------------------+------------------------------------------------------+-------------------------+---------------------------------------------------------------------------------------------------------+
89+ This scheme incurs a global error of order with six velocity evaluations.
90+
91+
92+ +-----------------------------+-------------------------------+----------------------------+---------------------------------+------------------------------+-----------------------------+--------------------------+
93+ | :math: `0 ` | | | | | | |
94+ +-----------------------------+-------------------------------+----------------------------+---------------------------------+------------------------------+-----------------------------+--------------------------+
95+ | :math: `(5 \mp \sqrt {5 })/10 ` | :math: `(5 \mp \sqrt {5 })/10 ` | | | | | |
96+ +-----------------------------+-------------------------------+----------------------------+---------------------------------+------------------------------+-----------------------------+--------------------------+
97+ | :math: `(5 \pm \sqrt {5 })/10 ` | :math: `\mp \sqrt {5 }/10 ` | :math: `(5 \pm2 \sqrt {5 })/10 ` | | | | |
98+ +-----------------------------+-------------------------------+----------------------------+---------------------------------+------------------------------+-----------------------------+--------------------------+
99+ | :math: `(5 \mp \sqrt {5 })/10 ` | :math: `(-15 \pm7 \sqrt {5 })/20 ` | :math: `(-1 \pm \sqrt {5 })/4 ` | :math: `(15 \mp7 \sqrt {5 })/10 ` | | | |
100+ +-----------------------------+-------------------------------+----------------------------+---------------------------------+------------------------------+-----------------------------+--------------------------+
101+ | :math: `(5 \pm \sqrt {5 })/10 ` | :math: `(5 \mp \sqrt {5 })/60 ` | :math: `0 ` | :math: `1 /6 ` | :math: `(15 \pm7 \sqrt {5 })/60 ` | | |
102+ +-----------------------------+-------------------------------+----------------------------+---------------------------------+------------------------------+-----------------------------+--------------------------+
103+ | :math: `(5 \mp \sqrt {5 })/10 ` | :math: `(5 \pm \sqrt {5 })/60 ` | :math: `0 ` | :math: `(9 \mp5 \sqrt {5 })/12 ` | :math: `1 /6 ` | :math: `(-5 \pm3 \sqrt {5 })/10 ` | |
104+ +-----------------------------+-------------------------------+----------------------------+---------------------------------+------------------------------+-----------------------------+--------------------------+
105+ | :math: `1 ` | :math: `1 /6 ` | :math: `0 ` | :math: `(-55 \pm25 \sqrt {5 })/12 ` | :math: `(-25 \mp7 \sqrt {5 })/12 ` | :math: `5 \mp2 \sqrt {5 }` | :math: `(5 \pm \sqrt {5 })/2 ` |
106+ +-----------------------------+-------------------------------+----------------------------+---------------------------------+------------------------------+-----------------------------+--------------------------+
107+ | :math: `1 /12 ` | :math: `0 ` | :math: `0 ` | :math: `0 ` | :math: `5 /12 ` | :math: `5 /12 ` | :math: `1 /12 ` |
108+ +-----------------------------+-------------------------------+----------------------------+---------------------------------+------------------------------+-----------------------------+--------------------------+
109+
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119112.. _ftlefinal :
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