<%namespace name="tools" file="tools.tex"/>

In test T1 of the Deltflume H298 series \citep{Steetzel1987} scour hole development in front of a dune revetment is ivestigated. The test was carried out at a depth scale nd = 5 \citep{Vellinga1986} and the initial profile in the flume correponds to the reference profile for the Dutch Holland coast. At the dune foot (located at x = 193 m from the wave board and z = 3.80 m above the flumes floor) a concrete revetment is applied that covers almost the whole dune face (slope of 1:1.8). The lower end of the revetment is located at z = 2.5 m and the top end at z = 6.2 m. The test was conducted with a constant water level (set at z = 4.2 m) and wave conditions that correpsond to a Pierson Moskowitz spectrum with Hm0 = 1.52 m and Tp = 5.37s. The sand applied in the test has a median grain diameter ($D_{50}$) of approximately 210 um.

Simulated and measured profile development during T1 are compared in (\autoref{fig:DeltaflumeH298_T1_fig1}). In the physical experiment the scour hole devlops till a depth of z = 2.59 m above after seven hours simulation (is 1.21 meter below the dune foot). Computed bedlevel changes for sources and sinks (sourcesink=1) versus sediment transport gradients (sourcesink=0) are comparable. Without any relevant model improvements it is concluded that XBeach underestimates the erosion depth at the toe of the revetment. It seems an explaination may be found in simulated sediment suspensions in the proximity of the revtment, which are underestimated with a factor two (\autoref{fig:DeltaflumeH298_T1_fig2}). The simulated mean flow is supposed to be in reasonable agreement with measurements.

${tools.image('DeltaflumeH298/T1/', 'fig1.eps')}
${tools.image('DeltaflumeH298/T1/', 'fig2.eps')}
${tools.table('DeltaflumeH298/T1/', 'skills.tex')}