Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Robust and fast online identification of streamwise vortices properties
  for closed-loop control purposes   We propose to combine the active vortex generators with the particle image
velocimetry (PIV) measurements and post-processing streamwise vortex
characterization algorithms into a feedback based closed-loop control system
for wind turbine applications. We develop two vortex identification and
characterization methods that use PIV realizations for the purpose of a
real-time (online or on-the-fly) feedback-based control. Both methods can
extract centers and strengths of streamwise vortices generated behind active
vortex generators in a turbulent boundary layer flow, and we show how to
integrate those in a closed-loop control strategy. For demonstration purposes
we use stereoscopic PIV measurements at the wind tunnel facility obtained in
the transverse-wall-normal plane behind active vortex generators. A robust
algorithm is using the $Q$-criteria and the integration of vorticity of each
extracted vortex. Results show that a moving window average of a small number
of instantaneous fields is nevertheless needed for increased robustness. The
robust method requires the full field PIV computation followed by spatial
derivatives calculations. A faster method is developed, which, using only
horizontal lines of vertical velocity, has a high potential to significantly
cut down the computational effort relative to the robust method. We compare the
two methods and discuss their shortcomings and the potential for the real-time,
online, closed-loop control of turbulent boundary layers of the wind turbine
blades.

23
The categories of this paper are: solv-int
2
The categories of this paper are: math
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci