Results from Experiments conducted at LNEC during 2016

Objectives

• Damage, runup and overtopping characterization under variable and unsteady test conditions of a rubble mound breakwater section
• Approach: Physical model tests of a breakwater section
  • 2D damage, runup and overtopping tests for a rock armour slope
  • 2D runup and overtopping tests with an impermeable smooth (pespex) slope

Methodology

• Methodology:
  • Section of:
    • a rock armour 1:2 slope
    • a 1:2 impermeable slope structure
      
      
      Figure 1. LNEC’s wave flume
      
      
      Figure 2. Model setup
      
      
      Figure 3: Breakwatercrosssection
  • Establish of variable test condition
    • 2D damage, runup and overtopping tests for a rock armour slope
    • A - Standard cumulative storm build-up (wave height increases) with increasing water level
    • B - Standard cumulative storm build-up with constant water level
    • C - Constant wave period (instead of constant steepness)
    • D - Standard storm build-up, constant water level, rebuilding
    • D* - Standard cumulative storm build-up (wave height increases) with varying water level
    • 2D runup and overtopping tests with an impermeable slope
    • E - Scaled HR Wallingford conditions
      
      Table 1. Test conditions
      
  • Test and measurements
    • Free surface elevation (with wave gauges)
    • Run-up (with wave gauge and video)
    • Wave Overtopping - both mean and wave-by-wave – (with load cell and wave gauges
    • Damage evolution (visual and using photogrammetry)
  • Analysis of results
    
    
• Temporal analysis of the free surface elevation
  
  
  
  
• Spectral analysis of the free surface elevation
  
  
  
  
• Free surface elevation: Results: Hs – Tests 1 – 7
  
  
  
  
• Free surface elevation: Repetitions HS
  
  
  
  
• Run-up
  
  
  
  
• Overtopping
  
  

Next steps

• Spectral analysis of the free surface elevation measurements using wavelet transform to evaluate the variation of Tp and spectral density energy throughout the entire test
• Wave run-up measurements using video image analysis
• Damage progression assessment using the damage average calculated for all the surveyed profiles and using the total eroded volume of the surveyed envelope.
• Damage progression assessment using the dimensionless damage depth parameter (E)