TY - JOUR
T1 - Scaled versus real-scale tests
T2 - Identifying scale and model errors in wave damping through woody vegetation
AU - Kalloe, Su A.
AU - Hofland, Bas
AU - Van Wesenbeeck, Bregje K.
PY - 2024
Y1 - 2024
N2 - Vegetation in front of levees, dikes and seawalls can decrease wave energy and therefore contribute to the safety against flooding. However, wave damping predictions by vegetation are still inaccurate due to measurement and modelling uncertainties. Many studies focused on finding reliable predictive tools using scaled flume tests with vegetation mimics. Scaling down vegetation can however lead to discrepancies with realistic scales, known as scale errors. In this work scaled tests were conducted on 3D-printed elastic replicas of willow trees and compared with real-scale experiments. We identified differences in measured wave dissipation between the scaled hydraulic model (1:10) and its real-scale prototype with 5m high live willow trees under storm conditions (1:1). The maximum measured wave damping (30%) was roughly 1.5 times higher than the real-scale experiments (20%). Following the same trend of the real-scale experiments, this amount of wave height damping declined for larger water levels. Largest effects are argued to be due to increased viscous damping (smaller branch Reynolds numbers) and non-exact flexibility scaling. These significant deviations illustrate that full-scale experiments, although expensive, are still needed to validate the results of scaled experiments for woody vegetation. Alternatively, accounting for these discrepancies can make scaled experiments more reliable and expensive real-scale experiments less needed for wave damping studies on woody vegetation.
AB - Vegetation in front of levees, dikes and seawalls can decrease wave energy and therefore contribute to the safety against flooding. However, wave damping predictions by vegetation are still inaccurate due to measurement and modelling uncertainties. Many studies focused on finding reliable predictive tools using scaled flume tests with vegetation mimics. Scaling down vegetation can however lead to discrepancies with realistic scales, known as scale errors. In this work scaled tests were conducted on 3D-printed elastic replicas of willow trees and compared with real-scale experiments. We identified differences in measured wave dissipation between the scaled hydraulic model (1:10) and its real-scale prototype with 5m high live willow trees under storm conditions (1:1). The maximum measured wave damping (30%) was roughly 1.5 times higher than the real-scale experiments (20%). Following the same trend of the real-scale experiments, this amount of wave height damping declined for larger water levels. Largest effects are argued to be due to increased viscous damping (smaller branch Reynolds numbers) and non-exact flexibility scaling. These significant deviations illustrate that full-scale experiments, although expensive, are still needed to validate the results of scaled experiments for woody vegetation. Alternatively, accounting for these discrepancies can make scaled experiments more reliable and expensive real-scale experiments less needed for wave damping studies on woody vegetation.
KW - 3D-printed tree mimics
KW - Pollard willow trees
KW - Scaled model
KW - Wave attenuation
UR - http://www.scopus.com/inward/record.url?scp=85189565153&partnerID=8YFLogxK
U2 - 10.1016/j.ecoleng.2024.107241
DO - 10.1016/j.ecoleng.2024.107241
M3 - Article
AN - SCOPUS:85189565153
SN - 0925-8574
VL - 202
JO - Ecological Engineering
JF - Ecological Engineering
M1 - 107241
ER -