LABORATORY EFFECTS IN BEACH STUDIES 
Volume VII. Movable-Bed Experiments With H,/L, = 0.013 
by 
Charles B. Chesnutt and Robert P. Stafford 
I. INTRODUCTION 
1. Background. 
Transverse waves caused by a gap at the end of the generator blade 
can affect the transport of sediment and create significant wave height 
variability. Madsen (1974) defined transverse waves in his development 
of the theory for a three-dimensional wavemaker. He pointed out that 
transverse waves can be generated for a water depth of 2.33 feet (0.71 
meter), a tank width of 10 feet (3.0 meters), and a wave period of 2.35 
seconds used in the two experiments reported here, and that transverse 
waves were probably the source of the considerable wave height varia- 
bility observed by Fairchild (1970) for the same wave period, tank 
width, water depth, and wave generators. 
The two experiments in this study offered an unplanned opportunity 
to quantify the effect of transverse waves on sediment transport. One 
experiment was conducted in a 6-foot-wide (1.8 meters) wave tank with- 
out a gap at either end of the blade, which made it essentially a control 
tank against which the other experiment was measured. The other experi- 
ment was conducted in a 10-foot-wide wave tank with a 0.15-foot (4.6 
centimeter gap at one end of the blade. 
These experiments (when designed) were conducted primarily to relate 
the variation of wave heights to the variation of wave reflection caused 
by changes in the movable-bed profile; and also, to define the equilibrium 
profile shape, at which point it was assumed that the wave height varia- 
bility would be significantly reduced, and to identify tank width effects. 
The Laboratory Effects in Beach Studies (LEBS) project was initiated 
at the Coastal Engineering Research Center (CERC) in 1966 to investigate 
the cause of wave height variability and other problems associated with 
movable-bed coastal engineering studies. Ten movable-bed laboratory 
experiments were conducted from 1970 to 1972 in the CERC Shore Processes 
Test Basin (SPTB) to measure the variation in reflection as the profile 
developed toward equilibrium. These LEBS experiments are reported in a 
series of eight volumes. This report (Vol. VII) describes two experi- 
ments conducted with H,/L> = 0.013. Volumes II, III, and IV (Chesnutt 
and Stafford, 1977a, 1977b, and 1977c) discussed five experiments con- 
ducted with Hj/Lo = 0.021; Volume V (Chesnutt and Stafford, 1977d) dis- 
cussed one experiment with Hj/Lo = 0.039; and Volume VI (Chesnutt and 
S) 
