Analysis and control of the transient shipboard engagement behavior of rotor systems

Jonathan A. Keller, Edward Smith

Research output: Contribution to journalConference article

13 Citations (Scopus)

Abstract

The transient coupled aeroelastic flap-lag-torsion response of an articulated rotor during simulated rotor engagements is examined. The rotor is modeled using the finite element method and aerodynamics are modeled using a nonlinear quasi-steady blade element theory for a 360° angle of attack range. The blade equations of motion are time integrated in modal space for a specified rotor speed profile. The airwake around a simple ship geometry is calculated using the Parallel Unstructured Maritime Aerodynamics code. Two rotor locations on the flight deck are examined. Predicted aeroelastic results for the calculated ship airwakes are compared to previous results, which assumed simple airwake models. Tip deflections and blade bending moments using the calculated airwakes are two to three times greater than for the simple airwake models. The reduction of excessive tip deflections by increasing the collective pitch setting in the vulnerable period of the engagement is examined. It was found that the maximum downward tip deflections could be reduced by as much as half, but the blade bending moments could not be reduced due to excessive upward flapping of the rotor.

Original languageEnglish (US)
Pages (from-to)1064-1079
Number of pages16
JournalAnnual Forum Proceedings - American Helicopter Society
Volume1
StatePublished - Jan 1 1999

Fingerprint

Rotors
flight
mathematics
Bending moments
Aerodynamics
Ships
Flaps
Angle of attack
Torsional stress
Equations of motion
Finite element method
Geometry
time

All Science Journal Classification (ASJC) codes

  • Transportation
  • Aerospace Engineering

Cite this

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abstract = "The transient coupled aeroelastic flap-lag-torsion response of an articulated rotor during simulated rotor engagements is examined. The rotor is modeled using the finite element method and aerodynamics are modeled using a nonlinear quasi-steady blade element theory for a 360° angle of attack range. The blade equations of motion are time integrated in modal space for a specified rotor speed profile. The airwake around a simple ship geometry is calculated using the Parallel Unstructured Maritime Aerodynamics code. Two rotor locations on the flight deck are examined. Predicted aeroelastic results for the calculated ship airwakes are compared to previous results, which assumed simple airwake models. Tip deflections and blade bending moments using the calculated airwakes are two to three times greater than for the simple airwake models. The reduction of excessive tip deflections by increasing the collective pitch setting in the vulnerable period of the engagement is examined. It was found that the maximum downward tip deflections could be reduced by as much as half, but the blade bending moments could not be reduced due to excessive upward flapping of the rotor.",
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Analysis and control of the transient shipboard engagement behavior of rotor systems. / Keller, Jonathan A.; Smith, Edward.

In: Annual Forum Proceedings - American Helicopter Society, Vol. 1, 01.01.1999, p. 1064-1079.

Research output: Contribution to journalConference article

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AU - Smith, Edward

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N2 - The transient coupled aeroelastic flap-lag-torsion response of an articulated rotor during simulated rotor engagements is examined. The rotor is modeled using the finite element method and aerodynamics are modeled using a nonlinear quasi-steady blade element theory for a 360° angle of attack range. The blade equations of motion are time integrated in modal space for a specified rotor speed profile. The airwake around a simple ship geometry is calculated using the Parallel Unstructured Maritime Aerodynamics code. Two rotor locations on the flight deck are examined. Predicted aeroelastic results for the calculated ship airwakes are compared to previous results, which assumed simple airwake models. Tip deflections and blade bending moments using the calculated airwakes are two to three times greater than for the simple airwake models. The reduction of excessive tip deflections by increasing the collective pitch setting in the vulnerable period of the engagement is examined. It was found that the maximum downward tip deflections could be reduced by as much as half, but the blade bending moments could not be reduced due to excessive upward flapping of the rotor.

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