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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,
b. Study on beach profile changes on accretion or erosion due to wave actions
and sea levels with NEXC Block coastal protection structure model ,
Institut Penyelidikan Hidraulik Kebangsaan Malaysia (NAHRIM)
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National Hydraulic Institute of Malaysia (NAHRIM)