Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


osu1195629380.pdf (3.48 MB)

ETD Abstract Container

Abstract Header

Reduced order modeling, nonlinear analysis and control methods for flow control problems

Kasnakoglu, Cosku
http://rave.ohiolink.edu/etdc/view?acc_num=osu1195629380

Abstract Details

2007, Doctor of Philosophy, Ohio State University, Electrical Engineering.
Flow control refers to the ability to manipulate fluid flow so as to achieve a desired change in its behavior, which offers many potential technological benefits, such as reducing fuel costs for vehicles and improving effectiveness of industrial processes. An interesting case of flow control is cavity flow control, which has been the motivation of this study: When air flow passes over a shallow cavity a strong resonance is produced by a natural feedback mechanism, scattering acoustic waves that propagate upstream and reach the shear layer, and developing flow structures. These cause many practical problems including damage and fatigue in landing gears and weapons bays in aircrafts. Presently there is a lack of sufficient mathematical analysis and control design tools for flow control problems. This includes mathematical models that are amenable to control design. Recently reduced-order modeling techniques, such as those based on proper orthogonal decomposition (POD) and Galerkin projection (GP), have come to interest. However, a main issue with these models is that the effect of boundary conditions, which is where the control input is, gets embedded into system coefficients. This results in a form quite different from what one deals with in standard control systems framework, which is a set of ordinary differential equations (ODE) where the input appears as an explicit term. Another issue with the standard POD/GP models is that they do not yield to systems that have any apparent structure in their coefficients. This leaves one with little choice other than to neglect the nonlinearities of the models and employ standard linear control theory based designs. The research presented in this thesis makes an effort at closing the gaps mentioned above by 1) presenting a reduced-order modeling method utilizing a novel technique for input separation on POD/GP models, 2) introducing a technique based on averaging theory and center manifold theory so as to reveal certain structures embedded in the model, and 3) developing nonlinear analysis and control design approaches for the resulting model. The theory is complemented by examples and case studies as appropriate, including the case of cavity flow control.
Andrea Serrani (Advisor)
162 p.
flow control; cavity flow; nonlinear analysis; nonlinear control; proper orthogonal decomposition; Navier-Stokes; POD; Galerkin projection; GP; reduced order modeling; averaging theory; center manifold theory

Recommended Citations

Citations

  • Kasnakoglu, C. (2007). Reduced order modeling, nonlinear analysis and control methods for flow control problems [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1195629380

    APA Style (7th edition)

  • Kasnakoglu, Cosku. Reduced order modeling, nonlinear analysis and control methods for flow control problems. 2007. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1195629380.

    MLA Style (8th edition)

  • Kasnakoglu, Cosku. "Reduced order modeling, nonlinear analysis and control methods for flow control problems." Doctoral dissertation, Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1195629380

    Chicago Manual of Style (17th edition)

osu1195629380
2,704
© 2007, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.