41 lines
1.3 KiB
Python
41 lines
1.3 KiB
Python
import numpy as np
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import torch
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from pina.problem import SpatialProblem
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from pina.operators import nabla, grad, div
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from pina import Condition, Span, LabelTensor
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class Stokes(SpatialProblem):
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output_variables = ['ux', 'uy', 'p']
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spatial_domain = Span({'x': [-2, 2], 'y': [-1, 1]})
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def momentum(input_, output_):
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nabla_ = torch.hstack((LabelTensor(nabla(output_.extract(['ux']), input_), ['x']),
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LabelTensor(nabla(output_.extract(['uy']), input_), ['y'])))
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return - nabla_ + grad(output_.extract(['p']), input_)
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def continuity(input_, output_):
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return div(output_.extract(['ux', 'uy']), input_)
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def inlet(input_, output_):
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value = 2 * (1 - input_.extract(['y'])**2)
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return output_.extract(['ux']) - value
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def outlet(input_, output_):
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value = 0.0
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return output_.extract(['p']) - value
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def wall(input_, output_):
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value = 0.0
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return output_.extract(['ux', 'uy']) - value
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conditions = {
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'gamma_top': Condition(Span({'x': [-2, 2], 'y': 1}), wall),
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'gamma_bot': Condition(Span({'x': [-2, 2], 'y': -1}), wall),
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'gamma_out': Condition(Span({'x': 2, 'y': [-1, 1]}), outlet),
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'gamma_in': Condition(Span({'x': -2, 'y': [-1, 1]}), inlet),
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'D': Condition(Span({'x': [-2, 2], 'y': [-1, 1]}), [momentum, continuity]),
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}
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