Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: From bypass transition to flow control and data-driven turbulence
  modeling: An input-output viewpoint   Transient growth and resolvent analyses are routinely used to assess
non-asymptotic properties of fluid flows. In particular, resolvent analysis can
be interpreted as a special case of viewing flow dynamics as an open system in
which free-stream turbulence, surface roughness, and other irregularities
provide sources of input forcing. We offer a comprehensive summary of the tools
that can be employed to probe the dynamics of fluctuations around a laminar or
turbulent base flow in the presence of such stochastic or deterministic input
forcing and describe how input-output techniques enhance resolvent analysis.
Specifically, physical insights that may remain hidden in the resolvent
analysis are gained by detailed examination of input-output responses between
spatially-localized body forces and selected linear combinations of state
variables. This differentiating feature plays a key role in quantifying the
importance of different mechanisms for bypass transition in wall-bounded shear
flows and in explaining how turbulent jets generate noise. We highlight the
utility of a stochastic framework, with white or colored inputs, in addressing
a variety of open challenges including transition in complex fluids, flow
control, and physics-aware data-driven turbulence modeling. Applications with
time- or spatially-periodic base flows are discussed and future research
directions are outlined.

11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
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The categories of this paper are: solv-int
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The categories of this paper are: q-alg
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The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
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The categories of this paper are: q-fin
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The categories of this paper are: cmp-lg
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The categories of this paper are: quant-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: funct-an
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-th