You get what you test.
It is a simplistic, possibly blunt, way of saying that at-sea dynamic interface flight testing depends on a multitude of factors, primarily ship and aircraft availability and weather conditions. And it is expensive. All of those factors often limit wind-over-deck launch and recovery envelopes in which rotorcraft are permitted to operate to and from U.S. Navy air-capable ships.
The Dynamic Interface Virtual Environment program is an Office of Naval Research technology transition initiative aimed at developing, validating and implementing modeling and simulation tools that can augment and ultimately reduce or eliminate the amount of live flight testing.
What does Navy testing have to do with an Army research and development center? CRUSAID.
“Coupled Rotor/Upwind Ship Aerodynamic Interaction Data is an experimental test designed to acquire truth data for the validation and verification of DIVE M&S elements,” said Dr. Oliver Wong, associate director of Design, Simulation & Experimentation for the U.S. Army Combat Capabilities Development Command Aviation & Missile Center’s Technology Development Directorate.
CRUSAID is a 1/48th scale test in the AvMC 7 foot by 10 foot wind tunnel located at Moffett Field, California, intended to capture benchmark dataset for coupled rotor and ship air wake model validation. DEVCOM AvMC researchers are applying the Army’s HELIOS software to model the impact of recirculation on aircraft performance for various static and dynamic flight conditions. Calculations of the rotor wake circulation using different fidelity levels are validated against flight tests performed at the Naval Air Systems Command on the CONEX fixed elevation platform structure. HELIOS predictions are then compared with measured rotor performance data and velocity flow field measurements from the land-based, full-scale flight test.
“Once HELIOS is validated with existing data, HELIOS simulations can be carried out for various ship, aircraft configurations and flight conditions, thus drastically reducing the need for flight tests,” said Dr. Buvana Jayaraman, aerospace engineer for AvMC. “The digital model generated as a part of the current work can be used to support the program throughout the life cycle. This can result in significant savings in cost and time.”
The test includes an above-waterline model of a Navy LPD-17 San Antonio class ship, and both V-22 tiltrotor and UH-1Y single main rotor helicopter models. Key test data includes rotorcraft forces and moments, ship surface pressures, and particle image velocimetry flow field measurements.
AvMC and the Navy's partnership on the project is testament to the importance of collaboration across military services to support the Warfighter and how that alliance can also benefit both branches’ modernization efforts.
“The collaboration with Navy not only helps to further confidence in the predictive ability of Army’s HELIOS software, but also provides knowledge on the performance of tiltrotors in complex operating conditions,” Jayaraman said. “Lessons learned from V-22 can be used to understand future operations.”
The DEVCOM Aviation & Missile Center, headquartered at Redstone Arsenal, Alabama, is the Army’s research and development focal point for advanced technology in aviation and missile systems. It is part of the U.S. Army Combat Capabilities Development Command (DEVCOM), a major subordinate command of the U.S. Army Futures Command. AvMC is responsible for delivering collaborative and innovative aviation and missile capabilities for responsive and cost-effective research, development and life cycle engineering solutions, as required by the Army’s strategic priorities and support to its Cross-Functional Teams.