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3 EXPERIMENTAL SETUP
Malaysia Water Research Journal
Physical tests were conducted using a 50m - 2D wave flume facility located
at Hydraulic and Instrumentation Lab, National Hydraulic Research Institute of
Malaysia (NAHRIM). Model structure dimension and hydrodynamic parameters
are geometrically downscaled to 1:20. Mildly sloping shore 1:15 and steep slope
1:3 are used representing actual beach profiles at selected sites. Cohesive-form
sediment size is 100μm. Three water levels; Mean Lower Low Water (MLLW) 0.9m,
Mean Sea Level (MSL) 1.0m and Mean Higher High Water (MHHW) 1.1m with two
significant wave height values Hs (irregular waves) 0.1m and 0.2m are used for
simulations. During the study, model structure is placed at a fix location along the
flume, approximately at the centre of interest study area i.e. in active erosion /
accretion zone. Beach profile is measured in the area of interest of 2.5m x 1.5m
both before and after each simulation for erosion-accretion and stability analysis.
Simulation run-time is 60 minutes referring to the duration of specific water level
in each tide cycle. Simulation on empty unprotected beach without structure
is also carried out as reference profile. Wave height and period is calibrated
both manually and automatically using 3 units of wave probe located along the
flume.
Figure 2. Experimental work in 2D wave flume facility
Interaction between waves and waves-structures due to variation of water
levels and wave heights are studied and recorded. The scope of simulation works
is simplified as below:
a. Study on beach profile changes on accretion or erosion due to wave
actions and sea levels on an exposed / unprotected beach (No Structure)
as a control,
Institut Penyelidikan Hidraulik Kebangsaan Malaysia (NAHRIM)
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National Hydraulic Institute of Malaysia (NAHRIM)