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Background
This project addresses the hydraulic resistance
of unlined (rough) hydropower tunnels, essential
both for power production and flood control.
The determination of the hydraulic capacity of
such tunnels requires the knowledge of friction
factors whose determination is mostly based
on empirical approaches. Thus, despite their
significance, friction factors can be considered
as the weakest component in the design of
tunnel waterways.
Methodology and Outcomes
This aspect is tackled through a combination
of analytical considerations, physical scale
model studies, and numerical simulations.
•
Novel roughness parameters will be defined
on the basis of a statistical analysis of
high res. tunnel digital elevation models,
obtained through Terrestrial Laser
Scanning.
•
Friction losses and the flow field measured
in scale model studies with miniature
versions of the tunnels constructed through
computer-controlled milling.
•
Assessment of roughness parameters and
friction losses with regard to the excavation
method => improved protocols for physical
scale studies used for the design of tunnels.
•
High resolution 3D-numerical simulations
validated by extensive PIV measurements
on the scale model data.
Illustrations of wall roughness in unlined tunnels.
Taken from Trinh Q.N., Holmøy K.H., Grøv E. (2015):
”Rock engineering service for unlined hydropower tunnels
in Vietnam”, Vietrock2015, 12-13March 2015, Hanoi,
Vietnam.
Department of Civil
and Environmental
Engineering
2016-2019
Linking Physical Wall
Roughness of Unlined
Tunnels to Hydraulic
Resistance
Supervisor:
Jochen Aberle
Co-supervisor:
Nils Reidar B. Olsen
Pierre-Yves Henry
POST DOC.
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