Calculations of Ice Shapes on Oscillating Airfoils

Narducci, Robert; Reinert, Tonja

doi:10.4271/2011-38-0015

Cited by 7 publications

(5 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The following results show the application of quasi-steady and quasi-unsteady approaches to an oscillating airfoil under several icing conditions tested in the NASA Glenn Icing Research Tunnel (IRT) 6,10 . These tests considered a Sikorsky SC2110 airfoil of 15-inch chord.…”

Section: A Test Case and Meshmentioning

confidence: 98%

“…), say from mid-span to blade tip 4 . Recently, a quasi-steady approach using different azimuthal aerodynamic conditions has been suggested to improve the prediction of ice shapes [5][6][7] . In this method, the time history of the rotor is represented by a very slow moving blade with one or two cycles for the total exposure time, after which a quasisteady simulation was implemented at a number of aerodynamic conditions corresponding to different azimuthal angles.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Quasi-Unsteady Icing Simulation of an Oscillating Airfoil

Fouladi

Aliaga²,

Habashi

2015

7th AIAA Atmospheric and Space Environments Conference

View full text Add to dashboard Cite

Over the last two decades, steady-state and quasi-steady computational techniques have been proposed and used to model ice accretion on helicopter rotors in both hover and forward flight. These methods cannot accurately predict ice shapes or their aerodynamic impact on rotor performance, particularly in forward flight due to its unsteady nature. The current study proposes a methodology to predict ice accretion on oscillating airfoils with varying angles of attack. The computation of the airflow, droplet impingement, and ice accretion is carried out in an unsteady framework that preserves the characteristics of air, water droplets and ice accretion with respect to time. Application of this approach to an oscillating airfoil shows good agreement with experiments. Nomenclature l C = lift coefficient d C = drag coefficient f = oscillation frequency ( Hz ) i = time step number k = the total number of icing time step at each shot ( * k n m  ) LWC = liquid water content ( 3 / g m ) m = total number of saved multiphase solutions of a cycle MVD = droplet mean volumetric diameter ( m  ) n = total number of cycles of a shot h Q  = convective heat flux ( / j s ) T = oscillation period ( s ) T  = air temperature at infinity ( C  ) . total t = total exposure time to icing condition ( s ) U  = air speed at infinity ( / m s ) u a = air velocity vector ( / m s ) u d = droplet velocity vector ( / m s )  = pitching angle ( deg ) . ave  = average pitching angle ( deg ) . osc  = oscillating pitching angle ( deg )  = collection efficiency 1 Ph.D. Candidate, Member AIAA. 2 total  = total collection efficiency t  = prescribed time step of ice accretion (s) a  = air density ( 3 / kg m ) wall  = air wall shear stress tensor ( 2 / N m )  = azimuthal angle ( rad )

show abstract

Section: A Test Case and Meshmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Quasi-Unsteady Icing Simulation of an Oscillating Airfoil

Fouladi

Aliaga²,

Habashi

2015

7th AIAA Atmospheric and Space Environments Conference

View full text Add to dashboard Cite

show abstract

“…These experimental tests were then the basis for validation of high-fidelity computational rotorcraft icing tools (Refs. 23,24). This work focuses on the validation of the oscillating airfoil test and uses the experimental test data from Reinert et al (Ref.…”

Section: Introductionmentioning

confidence: 99%

“…As part of this collaboration between the US Government and industry, The Boeing Company calculated ice shapes on an oscillating airfoil (Ref. 24) and used the experimental work conducted in the NASA Icing Research Tunnel (IRT) (Ref. 21) to validate the code.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Simulation and Analysis of Oscillating Airfoil Ice Shapes via a Fully Unsteady Collection Efficiency Approach

Morelli¹,

Guardone²,

Zhou³

2019

Proceedings of the Vertical Flight Society 75th Annual Forum

View full text Add to dashboard Cite

The aerodynamics associated with complex ice shapes degrades performance characteristics and handling qualities of rotorcraft. As a consequence, it generates high compensatory workloads for pilots making it difficult to fly in icing environments. Simulating rotorcraft icing is challenging as rotor blades experience flows at high Mach numbers which regularly produces difficult to predict mixed rime-glaze ice shapes. In conjunction with this, the motion of the blade during each revolution produces unsteady flow field behaviour and so unsteady ice accretion needs to be considered. A fully unsteady collection efficiency approach is hereby introduced to study the ice shapes formed on an oscillating rotor airfoil. The work focuses solely on two different test cases which produce largely different ice shapes caused entirely by different ice regimes. The ice shapes are measured and compared against icing wind tunnel experimental test data and prior calculations using a different approach for computing the ice thickness. These ice structures are then subject to analyses to assess possible performance degradation against the performance of a clean airfoil. Additionally, a computational aeroacoustic study investigates the possibility of using noise to detect different types of ice formation to help aid warning the pilot of dangerous icing conditions.

show abstract