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Coupled mode analysis of unsteady multistage flows in turbomachinery

Publication ,  Journal Article
Silkowski, PD; Hall, KC
Published in: Journal of Turbomachinery, Transactions of the ASME
1998

A computational method is presented for predicting the unsteady aerodynamic response of a vibrating blade row that is part of a multistage turbomachine. Most current unsteady aerodynamic theories model a single blade row isolated in an infinitely long duct. This assumption neglects the potentially important influence of neighboring blade rows. The present `coupled mode' analysis is an elegant and computationally efficient method for modeling neighboring blade row effects. Using this approach, the coupling between blade rows is modeled using a subset of the so-called spinning modes, i.e., pressure, vorticity, and entropy waves, which propagate between the blade rows. The blade rows themselves are represented by reflection and transmission coefficients. These coefficients describe how spinning modes interact with, and are scattered by, a given blade row. The coefficients can be calculated using any standard isolated blade row model; here we use a linearized full potential flow model together with rapid distortion theory to account for incident vortical gusts. The isolated blade row reflection and transmission coefficients, interrow coupling relationships, and appropriate boundary conditions are all assembled into a small sparse linear system of equations that describes the unsteady multistage flow. A number of numerical examples are presented to validate the method and to demonstrate the profound influence of neighboring blade rows on the aerodynamic damping of a cascade of vibrating airfoils.

Duke Scholars

Published In

Journal of Turbomachinery, Transactions of the ASME

Publication Date

1998

Volume

120

Issue

3

Start / End Page

410 / 421

Related Subject Headings

  • Mechanical Engineering & Transports
  • 4012 Fluid mechanics and thermal engineering
  • 4001 Aerospace engineering
  • 0913 Mechanical Engineering
  • 0901 Aerospace Engineering
 

Citation

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ICMJE
MLA
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Silkowski, P. D., & Hall, K. C. (1998). Coupled mode analysis of unsteady multistage flows in turbomachinery. Journal of Turbomachinery, Transactions of the ASME, 120(3), 410–421.
Silkowski, P. D., and K. C. Hall. “Coupled mode analysis of unsteady multistage flows in turbomachinery.” Journal of Turbomachinery, Transactions of the ASME 120, no. 3 (1998): 410–21.
Silkowski PD, Hall KC. Coupled mode analysis of unsteady multistage flows in turbomachinery. Journal of Turbomachinery, Transactions of the ASME. 1998;120(3):410–21.
Silkowski, P. D., and K. C. Hall. “Coupled mode analysis of unsteady multistage flows in turbomachinery.” Journal of Turbomachinery, Transactions of the ASME, vol. 120, no. 3, 1998, pp. 410–21.
Silkowski PD, Hall KC. Coupled mode analysis of unsteady multistage flows in turbomachinery. Journal of Turbomachinery, Transactions of the ASME. 1998;120(3):410–421.

Published In

Journal of Turbomachinery, Transactions of the ASME

Publication Date

1998

Volume

120

Issue

3

Start / End Page

410 / 421

Related Subject Headings

  • Mechanical Engineering & Transports
  • 4012 Fluid mechanics and thermal engineering
  • 4001 Aerospace engineering
  • 0913 Mechanical Engineering
  • 0901 Aerospace Engineering