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Investigation of Shock-Boundary Layer Interactions Over Deforming Surfaces: Fluid-Structural Coupling and Flow Control Mechanisms /

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Investigation of Shock-Boundary Layer Interactions Over Deforming Surfaces: Fluid-Structural Coupling and Flow Control Mechanisms // James Lawrence Fields.
作者:	Fields, James Lawrence,
面頁冊數:	1 electronic resource (282 pages)
附註:	Source: Dissertations Abstracts International, Volume: 87-05, Section: B.
Contained By:	Dissertations Abstracts International87-05B.
標題:	Aerospace engineering. -
電子資源:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=32384454
ISBN:	9798297962903

Investigation of Shock-Boundary Layer Interactions Over Deforming Surfaces: Fluid-Structural Coupling and Flow Control Mechanisms /
Fields, James Lawrence,

Investigation of Shock-Boundary Layer Interactions Over Deforming Surfaces: Fluid-Structural Coupling and Flow Control Mechanisms /James Lawrence Fields. - 1 electronic resource (282 pages)

Source: Dissertations Abstracts International, Volume: 87-05, Section: B.

High-speed aircraft operate in harsh and complex aerodynamic environments, presenting numerous challenges to vehicle designers. Complications frequently arise due to shock-boundary layer interactions (SBLIs), which are associated with several forms of performance losses. Further, SBLIs apply severe thermomechanical loads to structural skin panels and increase the prominence of potentially detrimental fluid-structural coupling. Understanding and mitigating the adverse effects of such interactions is crucial for design optimization, survivability, and certification of high-speed vehicles.This dissertation seeks to address open questions at the intersection of high-speed fluid structure interactions (FSI) and flow control by investigating SBLIs over deforming surfaces. The problem is studied using a combination of high-fidelity numerical simulations and various modal-based techniques. This approach allows for targeted exploration of both prescribed and compliant surface motions with the intent of revealing fluid-structural coupling and flow control mechanisms.The flow response of a laminar SBLI to prescribed surface motions is explored first. Parametric sweeps over classical standing and traveling mode shapes are considered at low-, moderate-, and high-frequency conditions for fluid-structure interaction. Attention is placed on phenomenologically describing the SBLI response to a variety of surface motions and on identifying potential mechanisms for controlling the shock-induced separation bubble. A key finding from this study is the characterization of the transition between quasi-steady and unsteady separation bubble responses. The transition occurs as the surface mode number and oscillation frequency are increased, driving unsteady flow dynamics such as shear layer shedding. Importantly, the links between the unsteady separation bubble dynamics, shear layer shedding, and separation control are established, motivating the ensuing flow control and FSI studies. Next, a deep investigation into the role of shear layer shedding is conducted. More specifically, the approach involves a resolvent analysis of the laminar SBLI base flow followed by large eddy simulations (LES) embedded with disturbances derived from the resolvent forcing modes. The resolvent analysis is used first to extract the optimal forcing/response properties of the Kelvin-Helmholtz (K-H) instability in the shear layer, whose modulation is known to enable separation control and may play a role in the fluid-structural coupling between SBLI and compliant surfaces. A forcing strategy is then devised from the resolvent forcing modes to inform an LES campaign. Applying resolvent-informed forcing to the SBLI enables a determination of the surface motions required to trigger the K-H instability and the subsequent separation control authority and mechanisms. The results indicate that the resolvent-informed forcing procedure yields valuable insights for designing flow control with distributed actuation via transpiration or surface motion. The role of aeroelastic coupling is also investigated. For the selected conditions, the aeroelastic response is characterized by transient behavior over long time scales modulated by coupling between high-order panel deflections and the K-H instability. The initial response is dominated by first- and second-mode panel deflections. Over time, a frequency lock-in occurs between K-H waves in the shear layer and high-order modes in the panel, resulting in mutual growth. The growth of the K-H instability leads to a period of cascading frequency and modal content in which energy is channeled into several discrete oscillating panel modes. It is shown that the frequency cascade is associated with nonlinear interactions between panel modes. The final state of the aeroelastic system is classified as a multi-mode limit cycle oscillation and exhibits traveling wave flutter. The time-mean flow field also exhibits favorable reductions in the separation bubble volume and downstream boundary layer thickness, supporting the notion of leveraging such fluid-structure interactions for passive flow control.Finally, the resolvent analysis methodology is extended to investigate a SBLI with an incoming turbulent boundary layer. The base flow used is a Reynolds-averaged Navier-Stokes (RANS) solution of the Air Force Research Laboratory RC-19 wind tunnel configuration. The analysis addresses two main knowledge gaps. First, this study documents the forcing/response properties of a turbulent impinging SBLI. Three distinct flow dynamics are identified and described in detail: self-sustained low-frequency separation bubble breathing, low-mid-frequency separation bubble oscillations, and high-mid-frequency K-H shedding. Interestingly, the modes associated with K-H shedding exhibit similar properties to those found for the laminar SBLI, suggesting the existence of a common flow control mechanism. However, differences in the optimal K-H forcing modes suggest that distinct control strategies are required. This work also fills a second knowledge gap by demonstrating the viability of the RANS-based resolvent approach, as the identified frequency content and flow dynamics align well with prior studies.

English

ISBN: 9798297962903Subjects--Topical Terms:

1002622
Aerospace engineering.
Subjects--Index Terms:

Aerodynamics

Investigation of Shock-Boundary Layer Interactions Over Deforming Surfaces: Fluid-Structural Coupling and Flow Control Mechanisms /
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520 $a High-speed aircraft operate in harsh and complex aerodynamic environments, presenting numerous challenges to vehicle designers. Complications frequently arise due to shock-boundary layer interactions (SBLIs), which are associated with several forms of performance losses. Further, SBLIs apply severe thermomechanical loads to structural skin panels and increase the prominence of potentially detrimental fluid-structural coupling. Understanding and mitigating the adverse effects of such interactions is crucial for design optimization, survivability, and certification of high-speed vehicles.This dissertation seeks to address open questions at the intersection of high-speed fluid structure interactions (FSI) and flow control by investigating SBLIs over deforming surfaces. The problem is studied using a combination of high-fidelity numerical simulations and various modal-based techniques. This approach allows for targeted exploration of both prescribed and compliant surface motions with the intent of revealing fluid-structural coupling and flow control mechanisms.The flow response of a laminar SBLI to prescribed surface motions is explored first. Parametric sweeps over classical standing and traveling mode shapes are considered at low-, moderate-, and high-frequency conditions for fluid-structure interaction. Attention is placed on phenomenologically describing the SBLI response to a variety of surface motions and on identifying potential mechanisms for controlling the shock-induced separation bubble. A key finding from this study is the characterization of the transition between quasi-steady and unsteady separation bubble responses. The transition occurs as the surface mode number and oscillation frequency are increased, driving unsteady flow dynamics such as shear layer shedding. Importantly, the links between the unsteady separation bubble dynamics, shear layer shedding, and separation control are established, motivating the ensuing flow control and FSI studies. Next, a deep investigation into the role of shear layer shedding is conducted. More specifically, the approach involves a resolvent analysis of the laminar SBLI base flow followed by large eddy simulations (LES) embedded with disturbances derived from the resolvent forcing modes. The resolvent analysis is used first to extract the optimal forcing/response properties of the Kelvin-Helmholtz (K-H) instability in the shear layer, whose modulation is known to enable separation control and may play a role in the fluid-structural coupling between SBLI and compliant surfaces. A forcing strategy is then devised from the resolvent forcing modes to inform an LES campaign. Applying resolvent-informed forcing to the SBLI enables a determination of the surface motions required to trigger the K-H instability and the subsequent separation control authority and mechanisms. The results indicate that the resolvent-informed forcing procedure yields valuable insights for designing flow control with distributed actuation via transpiration or surface motion. The role of aeroelastic coupling is also investigated. For the selected conditions, the aeroelastic response is characterized by transient behavior over long time scales modulated by coupling between high-order panel deflections and the K-H instability. The initial response is dominated by first- and second-mode panel deflections. Over time, a frequency lock-in occurs between K-H waves in the shear layer and high-order modes in the panel, resulting in mutual growth. The growth of the K-H instability leads to a period of cascading frequency and modal content in which energy is channeled into several discrete oscillating panel modes. It is shown that the frequency cascade is associated with nonlinear interactions between panel modes. The final state of the aeroelastic system is classified as a multi-mode limit cycle oscillation and exhibits traveling wave flutter. The time-mean flow field also exhibits favorable reductions in the separation bubble volume and downstream boundary layer thickness, supporting the notion of leveraging such fluid-structure interactions for passive flow control.Finally, the resolvent analysis methodology is extended to investigate a SBLI with an incoming turbulent boundary layer. The base flow used is a Reynolds-averaged Navier-Stokes (RANS) solution of the Air Force Research Laboratory RC-19 wind tunnel configuration. The analysis addresses two main knowledge gaps. First, this study documents the forcing/response properties of a turbulent impinging SBLI. Three distinct flow dynamics are identified and described in detail: self-sustained low-frequency separation bubble breathing, low-mid-frequency separation bubble oscillations, and high-mid-frequency K-H shedding. Interestingly, the modes associated with K-H shedding exhibit similar properties to those found for the laminar SBLI, suggesting the existence of a common flow control mechanism. However, differences in the optimal K-H forcing modes suggest that distinct control strategies are required. This work also fills a second knowledge gap by demonstrating the viability of the RANS-based resolvent approach, as the identified frequency content and flow dynamics align well with prior studies.
546 $a English
590 $a School code: 0168
650 4 $a Aerospace engineering. $3 1002622
650 4 $a Fluid mechanics. $3 528155
653 $a Aerodynamics
653 $a Shock boundary layer interaction
653 $a Fluid structure interactions
653 $a Flow control mechanisms
653 $a Resolvent analysis
653 $a Panel
690 $a 0538
690 $a 0204
710 2 $a The Ohio State University. $b Aerospace Engineering. $e degree granting institution. $3 3829383
720 1 $a McNamara, Jack J. $e degree supervisor.
773 0 $t Dissertations Abstracts International $g 87-05B.
790 $a 0168
791 $a Ph.D.
792 $a 2025
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=32384454