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Summary: 1
TESTING HIGH ANGLE WAVES INSTABILITY ON A LOW ENERGY
BEACH
A. Falqués1
, G. Medellín2
, R. Medina2
, M.González2
and M. Ávila1
Shoreline instability caused by very oblique wave incidence should develop only at
very large length and time scales on open ocean beaches. For this reason a direct
observation of this instability is difficult. On sheltered steep beaches those scales
can however be considerably smaller. We here analyze video observations of
shoreline position along El Puntal Spit in Santander (Spain) for a two-month event
where shoreline sand waves form, evolve and finally disappear. We then test
whether the observed sand waves could be governed by high angle waves instability.
Preliminary results show a quite good overall correspondence between observations
and instability model, in particular, regarding the wavelength (~125m). However,
the model predicts downdrift propagation while the sand wave does not appreciably
propagate.
INTRODUCTION
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