Annual Report 2016 - Mechanical Engineering

163 / 340

Flow Control and Aeroacoustics 163
Flow Control and Aeroacoustics
Numerical and experimental study of flow and sound fields and their control
n The focus of the research group in 2016 was the development and
testing of research tools for the numerical prediction of flow and sound
fields and for their validation in wind-tunnel experiments.
Sound Radiation from a 2-bladed Pusher Propeller
As a step towards better understanding of
installation effects on aerodynamic noise
generation, a pusher propeller configu­
ration is investigated. It can be installed
downstream of the V-shaped tail section
of an UAV (corresponding to the IMPULSS
geometry designed and built at LLS under
the auspices of Prof. M. Hornung). The
hybrid prediction approach consists of
Hans-Jakob.Kaltenbach
Phone +49.89.289.16397
Contact
Prof. Dr.-Ing.
Hans-Jakob Kaltenbach
Numerical Prediction of Aerodynamic Loads During Entry
of a Subway Train into an Underground Station
The wall cladding and other installations
in subway stations experience unsteady
aerodynamic loads during entry and pas-
sage of trains. The purpose of an ongoing
project is the quantitative prediction of
these loads by numerical simulation (CFD)
and possible verification by measure­
ments at real sites at a later stage. Up to
now, results from transient simulations
based on the sliding-mesh technique have
been obtained for generic train and station
geometries at parameters (train speed,
deceleration, blockage, distance of sta-
tions) corresponding to a typical situation
in the Munich subway system.
two steps. Firstly, an unsteady CFD simu-
lation employing sliding-mesh technique
is carried out in the time domain, yielding
unsteady pressure on the blade surface.
In a second step, the Ffowcs-Williams
Hawkings solver Spysi (developed at the
Friedrich-Alexander University of Erlangen
in the group of Prof. S. Becker) is employ-
ed to predict the farfield sound field.
Isosurface of the pressure field on a horizontal cut in 2m distance from the ground of the
subway station at an instance of time, when the train head has already entered the station
(from T. S. Klose, . thesis, 2016)
Isosurface of the magnitude of the
velocity vector in a cut along the
propeller axis (left) and through
the propeller plane (right).
(from M. Habryka, student thesis)