Modal analysis of the transonic shock process over a griffith-type, laminar-flow airfoil

Armando R.Collazo Garcia, Theresa Saxton-Fox, Phillip J. Ansell

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Proper orthogonal decomposition (POD) is applied to schlieren data of a Griffith-type transonic, laminar-flow airfoil across a range of angles of attack to analyze the influence boundary layer suction had on the shock oscillatory process. This particular class of airfoils utilizes active boundary-layer suction to assist an aggressive pressure recovery process near the trailing edge of the airfoil. In the absence of active suction, the boundary layer separates, producing a highly unsteady compressible flow. For the no-suction cases it was observed that the leading mode displayed unsteady perturbations applied about a coherent shock structure and its frequency associated with the time dependent amplitude agreed with the oscillatory peak frequency of 22.38 Hz identified in a previous study. Higher order modes were characterized by bidirectional fluctuations in the density gradient fields having shorter wavelengths and covering a spatial amplitude symmetric about the average shock location, effectively capturing the shock travel area. The shock structure under suction conditions appeared to have a lambda foot that originated from the same chordwise location as that produced from the no-suction case, but extended further downstream. The application of boundary-layer suction was observed to decrease the unsteadiness associated with the shock travel, relative to the no-suction cases. Lastly, a reduced order model (ROM) of the oscillatory process was produced based on the spectral characteristics of the first 10 modes whose amplitudes were assumed to follow a sinusoidal profile. The reconstruction was successful in identifying the relevant physics and spatial characteristics of the dynamical process without the associated unsteadiness present in the data.

Original languageEnglish (US)
Title of host publicationAIAA Scitech 2021 Forum
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
Pages1-16
Number of pages16
ISBN (Print)9781624106095
DOIs
StatePublished - 2021
EventAIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2021 - Virtual, Online
Duration: Jan 11 2021Jan 15 2021

Publication series

NameAIAA Scitech 2021 Forum

Conference

ConferenceAIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2021
CityVirtual, Online
Period1/11/211/15/21

ASJC Scopus subject areas

  • Aerospace Engineering

Fingerprint Dive into the research topics of 'Modal analysis of the transonic shock process over a griffith-type, laminar-flow airfoil'. Together they form a unique fingerprint.

Cite this