GLTRS--Glenn
TITLE AND SUBTITLE:
Physical Mechanisms of Glaze Ice Scallop Formations on Swept Wings

AUTHOR(S):
Mario Vargas and Eli Reshotko

REPORT DATE:
January 1998

FUNDING NUMBERS:
WU-548-20-23-00

PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration
Lewis Research Center
Cleveland, Ohio 44135-3191

PERFORMING ORGANIZATION REPORT NUMBER:
E-11037

SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration
Washington, DC 20546-0001

REPORT TYPE AND DATES COVERED:
Technical Memorandum

SPONSORING/MONITORING AGENCY REPORT NUMBER:
NASA TM-1998-206616
AIAA-98-0491

SUPPLEMENTARY NOTES:
Prepared for the 36th Aerospace Sciences Meeting & Exhibit sponsored by the American Institute of Aeronautics and Astronautics, Reno, Nevada, January 12-15, 1998. Mario Vargas, NASA Lewis Research Center and Eli Reshotko, Case Western Reserve University, Cleveland, Ohio 44106. Responsible person, Mario Vargas, organization code 5840, (216) 433-2064.

ABSTRACT:
An experiment was conducted to understand the physical mechanisms that lead to the formation of scallops on swept wings. Icing runs were performed on a NACA 0012 swept wing tip at 45º, 30º, and 15º sweep angles. A baseline case was chosen and direct measurements of scallop height and spacing, castings, video data and close-up photographic data were obtained. The results showed the scallops are made of glaze ice feathers that grow from roughness elements that have reached a minimum height and are located beyond a given distance from the attachment line. This distance depends on tunnel conditions and sweep angle, and is the critical parameter in the formation of scallops. It determines if complete scallops, incomplete scallops or no scallops are going to be formed. The mechanisms of growth for complete and incomplete scallops were identified. The effect of velocity, temperature and LWC on scallop formation was studied. The possibility that cross flow instability may be the physical mechanism that triggers the growth of roughness elements into glaze ice feathers is examined.

SUBJECT TERMS:
Icing; Swept wings; Ice scallop formations; Lobster tails; Cross flow vortices;
Cross flow instability; Swept wing ice accretions

NUMBER OF PAGES:
37

PDF AVAILABLE FROM URL:
1998/TM-1998-206616.pdf
(8,970,196 KB)
This page contains an Adobe® Acrobat® Reader PDF file. The PDF documents have been created to show thumbnails of each page. If the thumbnails do not display properly, download the file to the hard drive and view through Acrobat® Reader. You can download Acrobat® Reader for free. click

NASA NASA GLTRS--Glenn

A service of the NASA Glenn Research Center Logistics and Technical Information Division

Suggestions or questions about this site can be directed to:

NASA official: Technical Publications Manager, Sue.E.Butts@nasa.gov

Web curator: Caroline.A.Rist@grc.nasa.gov

Privacy Policy and Important Notices