Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Helical vortices generated by flapping wings of bumblebees   High resolution direct numerical simulations of rotating and flapping
bumblebee wings are presented and their aerodynamics is studied focusing on the
role of leading edge vortices and the associated helicity production. We first
study the flow generated by only one rotating bumblebee wing in circular motion
with $45^{\circ}$ angle of attack. We then consider a model bumblebee flying in
a numerical wind tunnel, which is tethered and has rigid wings flapping with a
prescribed generic motion. The inflow condition of the wind varies from laminar
to strongly turbulent regimes. Massively parallel simulations show that inflow
turbulence does not significantly alter the wings' leading edge vortex (LEV),
which enhances lift production. Finally, we focus on studying the helicity of
the generated vortices and analyze their contribution at different scales using
orthogonal wavelets.

14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
16
The categories of this paper are: stat
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc