Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Lift force on an asymmetrical obstacle immersed in a dilute granular
  flow   This paper investigates the lift force exerted on an elliptical obstacle
immersed in a granular flow through analytical calculations and computer
simulations. The results are shown as a function of the obstacle size,
orientation with respect to the flow direction (tilt angle), the restitution
coefficient and ellipse eccentricity. The theoretical argument, based on the
force exerted on the obstacle due to inelastic, frictionless collisions of a
very dilute flow, captures the qualitative features of the lift, but fails to
reproduce the data quantitatively. The reason behind this disagreement is that
the dilute flow assumption on which this argument is built breaks down as a
granular shock wave forms in front of the obstacle. More specifically, the
shock wave change the grains impact velocity at the obstacle, decreasing the
overall net lift obtained from a very dilute flow.

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The categories of this paper are: physics
12
The categories of this paper are: nucl-th
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org
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The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
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The categories of this paper are: math
34
The categories of this paper are: chem-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex