UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

More information is available at Theses and Dissertations at University of Maryland Libraries.

Browse

Filters

20051

Settings

Author: search.filters.author.Jose, Arun IsaacSubject: search.filters.subject.Engineering, Aerospace

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Unsteady Aerodynamic Modeling With Time-Varying Free-Stream Mach Numbers
    (2005-12-02) Jose, Arun Isaac; Leishman, John G; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The development of a reduced-order unsteady airfoil theory is described for application to non-steady, subsonic compressible flows with variable free-stream Mach number. The airfoil theory, which is suitable for application to most types of comprehensive helicopter rotor analyses, is developed for arbitrary, time-dependent combined variations in angle of attack and Mach number. The approach is validated using CFD solutions based on the Euler equations. The new model is developed using the indicial theory as a basis, and shows excellent agreement with direct CFD solutions for a wide range of practical flows. For supercritical flows, nonlinearities associated with the formation and movement of shock waves are observed in the CFD solutions, which the unsteady airfoil theory proves inadequate. Overall, this study shows that the reduced-order unsteady aerodynamic theory provides significant improvements in sectional airloads predictions over existing methods that might be used in various types of comprehensive helicopter rotor analyses.