Global instabilities and transient growth in Blasius boundary-layer flow over a compliant panel
|dc.identifier.citation||Tsigklifis, K. and Lucey, A. 2015. Global instabilities and transient growth in Blasius boundary-layer flow over a compliant panel. Sadhana - Academy Proceedings in Engineering Sciences. 40 (3): pp. 945-960.|
We develop a hybrid of computational and theoretical approaches suited to study the fluid–structure interaction (FSI) of a compliant panel, flush between rigid upstream and downstream wall sections, with a Blasius boundary-layer flow. The ensuing linear-stability analysis is focused upon global instability and transient growth of disturbances. The flow solution is developed using a combination of vortex and source boundary-element sheets on a computational grid while the dynamics of a plate-spring compliant wall are couched in finite-difference form. The fully coupled FSI system is then written as an eigenvalue problem and the eigenvalues of the various flow- and wall-based instabilities are analysed. It is shown that coalescence or resonance of a structural eigenmode with either a flow-based Tollmien–Schlichting Wave (TSW) or wall-based travelling-wave flutter (TWF) modes can occur. This can render the nature of these well-known convective instabilities to become global for a finite compliant wall giving temporal growth of system disturbances. Finally, a non-modal analysis based on the linear superposition of the extracted temporal modes is presented. This reveals a high level of transient growth when the flow interacts with a compliant panel that has structural properties which render the FSI system prone to global instability. Thus, to design stable finite compliant panels for applications such as boundary-layer transition postponement, both global instabilities and transient growth must be taken into account.
|dc.title||Global instabilities and transient growth in Blasius boundary-layer flow over a compliant panel|
|dcterms.source.title||Sadhana - Academy Proceedings in Engineering Sciences|
The final publication is available at Springer via 10.1007/s12046-015-0360-z
|curtin.department||Department of Mechanical Engineering|