Submarine Model in National Transonic Facility
(1986-L-09574): Like the Full-Scale Tunnel in 1950, the National Transonic Facility (NTF) has been used to evaluate submarine hull designs for the Navy.
Technician William Moore inspects a submarine model before resuming super-cold wind tunnel tests at NASA's Langley Research Center, Hampton, Virginia. The Navy and NASA teamed up to measure airflow about a scale model sub to gather fundamental scientific data that may prove valuable to Navy researchers.
The 20-foot submarine model is mounted upside down in the test section of Langley's National Transonic Facility (NTF). Measurements were made of the complicated flow at the stern of the model, an area important to studies of propeller inflow. The tests were run at high atmospheric pressures and at temperatures as low as minus 230 degrees Fahrenheit to better simulate potential operating conditions. If this is realized, sub designers will gain scaling laws that will eventually provide improved propulsion design methods. The tests were conducted for the David W. Taylor Naval Ship R&D Center and the Office of Naval Research.
The NTF is the largest cryogenic wind tunnel in the world and represents a significant engineering accomplishment. It achieves realistic fluid flow by the introduction of liquid nitrogen into the pressurized tunnel circuit. The super-cold nitrogen is sprayed into the high-speed flow, where it vaporizes into a gas much denser and less vicous than air, countering scaling inaccuracies due to relatively small model sizes. The result of this cryogenic test method is a highly accurate simulation of actual flight—or in this case, underwater operations. The tunnel is normally used to test the aerodynamic characteristics of aircraft and spacecraft.
Credit: NASA
Image Number: 1986-L-09574
Date: October 8, 1986
Submarine Model in National Transonic Facility
(1986-L-09574): Like the Full-Scale Tunnel in 1950, the National Transonic Facility (NTF) has been used to evaluate submarine hull designs for the Navy.
Technician William Moore inspects a submarine model before resuming super-cold wind tunnel tests at NASA's Langley Research Center, Hampton, Virginia. The Navy and NASA teamed up to measure airflow about a scale model sub to gather fundamental scientific data that may prove valuable to Navy researchers.
The 20-foot submarine model is mounted upside down in the test section of Langley's National Transonic Facility (NTF). Measurements were made of the complicated flow at the stern of the model, an area important to studies of propeller inflow. The tests were run at high atmospheric pressures and at temperatures as low as minus 230 degrees Fahrenheit to better simulate potential operating conditions. If this is realized, sub designers will gain scaling laws that will eventually provide improved propulsion design methods. The tests were conducted for the David W. Taylor Naval Ship R&D Center and the Office of Naval Research.
The NTF is the largest cryogenic wind tunnel in the world and represents a significant engineering accomplishment. It achieves realistic fluid flow by the introduction of liquid nitrogen into the pressurized tunnel circuit. The super-cold nitrogen is sprayed into the high-speed flow, where it vaporizes into a gas much denser and less vicous than air, countering scaling inaccuracies due to relatively small model sizes. The result of this cryogenic test method is a highly accurate simulation of actual flight—or in this case, underwater operations. The tunnel is normally used to test the aerodynamic characteristics of aircraft and spacecraft.
Credit: NASA
Image Number: 1986-L-09574
Date: October 8, 1986