July 3, 2012
Public Affairs Office
HANOVER, N.H. – ERDC Cold Regions Research and Engineering Laboratory’s (CRREL) flume in the Ice Engineering Facility was center stage for two weeks in May, as the National Science Foundation sponsored New York University’s (NYU) research into the phenomena of ice scallops. The project used the refrigerated bottom of the flume, which is believed to be the only venue with such a capability in the United States.
The facility simultaneously enabled air temperature control at about freezing; a refrigerated stream bed with three inches of ice with adjustable slope; and controllable water temperature. Dave Finnegan of CRREL’s Geographic Information Systems provided Light Detection and Ranging – LiDAR - data to determine the unique ice surface profiles required.
Ice scallops are a small-scale, quasi-periodic phenomenon that occurs at the ice-ocean interface. They have been observed on the tops, sides and undersides of icebergs and tend to have a characteristic period of five to 15 centimeters. Scallops resemble the dimple pattern on a golf ball and tend to arrange themselves in a hexagonal packing pattern. The formation of ice scallops is mechanically similar to the formation of bedforms in a riverbed or estuary. Increased understanding of the mechanics involved is expected to advance knowledge of both ice scallop formation and sediment transport/bedform formation.
NYU’s research is focused on determining the non-dimensional numbers that best characterize scallop formation. The Hanover-based experiment honed in on being able to produce a quantitative visualization of the flow field in a single scallop or group of scallops.