PREFACE 
Ten experiments were conducted at the Coastal Engineering Research 
Center (CERC) from 1970 to 1972 as part of an investigation of the Lab- 
oratory Effects in Beach Studies (LEBS), to relate wave height varia- 
bility to wave reflection from a movable-bed profile in a wave tank. 
The investigation also identified the effects of other laboratory con- 
straints. The LEBS project is directed toward the solution of problems 
facing the laboratory researcher or engineer in charge of a model study; 
ultimately, the results will be of use to field engineers in the analysis 
of model studies. The work was carried out under the CERC coastal pro- 
cesses program. 
This report (Vol. VII) is the seventh in a series of eight volumes 
on the LEBS experiments. Volume I describes the procedures used in the 
10 LEBS experiments, and also serves as a guide for conducting realistic 
coastal engineering laboratory studies; Volumes II to VII are data re- 
ports covering all experiments; Volume VIII summarizes the LEBS experi- 
ments detailed in the earlier volumes. 
This volume describes two movable-bed experiments in which the wave 
reflection variation and profile changes are shown to be affected by a 
transverse wave generated by gaps at the side of the generator blade. 
The experiments also show the effect of the initial distance between 
the generator and the profile on the profile development. 
This report was prepared by Charles B. Chesnutt, principal investi- 
gator, and Robert P. Stafford, senior technician in charge of the two 
experiments, under the general supervision of Dr. C.J. Galvin, Jr., 
Chief, Coastal Processes Branch. The authors acknowledge the assistance 
of Dr. 0.S. Madsen in identifying the sources of the wave height varia- 
bility and for his review of the manuscript. 
Comments on this publication are invited. 
Approved for publication in accordance with Public Law 166, 79th 
Congress, approved 31 July 1945, as supplemented by Public Law 172, 
88th Congress, approved 7 November 1963. 
yy Spee TE. 
JOHN H. COUSINS 
Colonel, Corps of Engineers 
Commander and Director 
