Analysis of the wake dynamics of stiff and flexible cantilever beams using POD and DMD

Cesur, Alper; Carlsson, Christian; Feymark, Andreas; Fuchs, László; Revstedt, Johan

doi:10.1016/j.compfluid.2014.05.012

Cited by 24 publications

(9 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Due to the difficulty in directly inverting the upper triangular matrix R, this algorithm becomes numerically ill-conditioned in case of noise contamination. To solve this problem, Schmid (2010) and Cesur et al (2014) constructed an alternative matrix S via similarity transformation (the second column in Table 1), while Duke et al (2012) applies a pseudo-inverse to R (the third column in Table 1). Both invoke a compact singular value decomposition, which implies a projection of system matrix A onto a POD basis-spanned vector space.…”

Section: Dmd Algorithmmentioning

confidence: 99%

On the accuracy of dynamic mode decomposition in estimating instability of wave packet

2015

View full text Add to dashboard Cite

Section: Dmd Algorithmmentioning

confidence: 99%

On the accuracy of dynamic mode decomposition in estimating instability of wave packet

2015

View full text Add to dashboard Cite

“…The dynamic mode decomposition (DMD) method proposed by Schmid (2010) provides a means to decompose the original flow into a series of modes, with each mode containing a single characteristic frequency and growth rate. Thus, it is suitable for the identification of the spatiotemporal coherent structures in periodic flows and has been used in the analyses of cavity flows (Seena & Sung 2011;Guéniat, Pastur & Lusseyran 2014), backward-facing step flows (Sampath & Chakravarthy 2014) and flows around cylinders (Thompson et al 2014;Zhang, Liu & Wang 2014;Stankiewicz et al 2016;Li et al 2019) and cantilever beams (Cesur et al 2014). More recently, the dynamic pressure field over a finite-height prism immersed in a boundary layer flow has been examined using DMD (Luo & Kareem 2021).…”

Section: Introductionmentioning

confidence: 99%

Global instability and mode selection in flow fields around rectangular prisms

et al. 2023

View full text Add to dashboard Cite

Large-eddy simulations of the unsteady flows around rectangular prisms with chord-to-depth ratios (B/D) ranging from 3 to 12 are carried out at a Reynolds number of 1000. A particular focus of the study is the physical mechanisms governing the global instability of the flow. The coherent structures and velocity spectra reveal that large-scale leading-edge vortices (L vortices) are formed by the coalescence of Kelvin–Helmholtz rollers. Based on dynamic mode decomposition, the interactions between the L vortex and the trailing-edge vortex (T vortex) at different B/D values are revealed. It is found that the phase difference between the L and T vortices is the critical factor promoting a stepwise increase in the Strouhal number with increasing B/D. According to the phase analysis, there are two types of pressure feedback-loop mechanisms maintaining the self-sustained oscillations. When B/D = 4–5, the feedback loop covers the separation region, and the global instability is controlled by the impinging shear-layer instability. When B/D = 3 and 6–12, the feedback loop covers the entire chord, and the global instability is controlled by the impinging leading-edge vortex shedding instability. Self-sustained oscillations of the shear layer still exist after a splitter plate is placed in the near wake, indicating that the T vortex shedding is not essential in triggering the global instability. Nevertheless, with the participation of the T vortex, the primary instability mode may be reselected due to the upper and lower limits of the shedding frequency imposed by the T vortex.

show abstract

“…On account of this, such studies have focused exclusively on limited regions of the flow-field that are outside the overall envelope of the structural motion, such as the wake behind immersed bodies. One such demonstration of DMD on the wake of a flapping membrane was carried out by Schmid (2010), and the decomposition of the wake behind a flexible cantilevered beam was performed by Cesur et al (2014). However, by limiting the region of interest in the flow-field to the wake, relevant flow structures close to the immersed body as well as within the shear layer are ignored.…”

Section: Introductionmentioning

confidence: 99%

Dynamic mode decomposition based analysis of flow over a sinusoidally pitching airfoil

Menon

Mittal

2020

Journal of Fluids and Structures

View full text Add to dashboard Cite

Dynamic mode decomposition (DMD) has proven to be a valuable tool for the analysis of complex flow-fields but the application of this technique to flows with moving boundaries is not straightforward. This is due to the difficulty in accounting in the DMD formulation, for a body of non-zero thickness moving through the field of interest. This work presents a method for decomposing the flow on or near a moving boundary by a change of reference frame, followed by a correction to the computed modes that is determined by the frequency spectrum of the motion. The correction serves to recover the modes of the underlying flow dynamics, while removing the effect of change in reference frame. This method is applied to flow over sinusoidally pitching airfoils, and the DMD analysis is used to derive useful insights regarding flow-induced pitch oscillations of these airfoils.

show abstract

Analysis of the wake dynamics of stiff and flexible cantilever beams using POD and DMD

Cited by 24 publications

References 19 publications

On the accuracy of dynamic mode decomposition in estimating instability of wave packet

On the accuracy of dynamic mode decomposition in estimating instability of wave packet

Global instability and mode selection in flow fields around rectangular prisms

Dynamic mode decomposition based analysis of flow over a sinusoidally pitching airfoil

Contact Info

Product

Resources

About