Accurate reconstruction of the surface roughness is of high importance to various
areas of science and engineering. One important application of this technology is
for remote monitoring of open channel flows through observing its dynamic surface
roughness. In this paper a novel airborne acoustic method of roughness reconstruction
is proposed and tested with a static rigid rough surface. This method is based
on the acoustic holography principle and Kirchhoff approximation which make use of
acoustic pressure data collected at multiple receiver points spread along an arch. The
Tikhonov regularisation and generalised cross validation (GCV) technique are used
to solve the underdetermined system of equations for the acoustic pressures. The
experimental data are collected above a roughness created with a 3D printer. For
the given surface it is shown that the proposed method works well with the various
number of receiver positions. In this paper, the tested ratios between the number
of surface points at which the surface elevation can be reconstructed and number of
receiver positions are 2.5, 5 and 7.5. It is shown that, in a region comparable with
the projected size of the main directivity lobe, the method is able to reconstruct the
spatial spectrum density of the actual surface elevation with the accuracy of 20%.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)