On an attempt to simplify the Quartapelle–Napolitano approach to computation of hydrodynamic forces in open flows

Protas, Bartosz

doi:10.1016/j.jfluidstructs.2007.05.002

Cited by 3 publications

(4 citation statements)

References 23 publications

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“…The main advantage of this method resides in not requiring the computation of the pressure field around the object to determine the forces. However, an accurate vorticity field is needed at the surface of the body to have reliable results (it was proved by Protas (2007) that the contribution from the vorticity at the boundary cannot be in fact eliminated in this approach). While the variational approach has been employed before in numerical studies, the present investigation is to the best of our knowledge its first application to experimental data.…”

Section: Discussionmentioning

confidence: 99%

Application of a variational approach to the computation of forces around a wing

et al. 2022

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In this paper we present an application of the variational approach, introduced by Quartapelle & Napolitano (1983) and developed further by Protas et al. (2000), which requires only the velocity fields and its derivatives to determine forces acting on a body. First, the approach is presented and adapted to our 3D test problem. The obtained expression for the hydrodynamic force involves a harmonic function η whose determination is also presented. Then, numerical flow fields obtained with LES are used in order to evaluate the influence of different parameters on the forces and to offer a validation of the proposed approach. This allows us to assess the accuracy of the method and its advantages.Next, a comparison of the proposed variational approach with the momentum equation approach presented by David et al. ( 2009) is discussed. The momentum equation approach offers a non-intrusive method to determine forces, but requires the pressure field around the object. On the other hand, the variational approach requires the determination of the vorticity field on the surface of the wing, which is not always trivial to obtain with sufficient accuracy, but the computation of the pressure field can be avoided. This paper aims to compare both methods in a practical setting and show their relative advantages and sensitivities to different

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Section: Discussionmentioning

confidence: 99%

Application of a variational approach to the computation of forces around a wing

et al. 2022

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“…Note that accurately capturing the vorticity field next to the body surface is a non-trivial challenge for the above expression. Let us consider the simple fact that, as described by Protas (2007), this above approach rapidly breaks down as vorticity advects away from the body of interest and across the control surface (field of view). To combat this limitation, Quartapelle and Napolitano (1983) developed a clever approach weighting vorticity closest to the body instead.…”

Section: Vorticity Formulationsmentioning

confidence: 99%

“…To combat this limitation, Quartapelle and Napolitano (1983) developed a clever approach weighting vorticity closest to the body instead. Despite attempts to reformulate this approach by Protas (2007), complete information regarding the wall-bounded vorticity around the body of interest is required, thus making the approach impractical for most physical experiments. For some excellent reviews of these diverse vorticity-based methods, the reader is also directed to the works of Protas et al (2000) and Graziani and Bassanini (2002).…”

Section: Vorticity Formulationsmentioning

confidence: 99%

Load-estimation techniques for unsteady incompressible flows

Rival

Oudheusden

2017

Exp Fluids

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“…To actually measure in vivo fluid forces non-intrusively, engineers invented control volume analysis to (simplify and) integrate the Navier-Stokes equations (Vincenti 1982). If the pressure field cannot be measured, then fluid forces and moments can be determined based on velocity and vorticity fields, which are generally determined either computationally or using particle image velocimetry (PIV) (Protas 2007;Howe 1995;Quartapelle and Napolitano 1983;Ragazzo and Tabak 2007;Magnaudet 2011;Wu 1981). Alternatively, the control volume analysis can be simplified by rewriting it into a control surface analysis (Lentink 2018;Rival and van Oudheusden 2017;Wu et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Fluid moment and force measurement based on control surface integration

Chin

Lentink

2019

Exp Fluids

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The moments and torques acting on a deforming body determine its stability and maneuverability. For animals, robots, vehicles, and other deforming objects locomoting in liquid or gaseous fluids, these fluid moments are challenging to accurately measure during unconstrained motion. Particle image velocimetry and aerodynamic force platforms have the potential to resolve this challenge through the use of control surface integration. These measurement techniques have previously been used to recover fluid forces. Here, we show how control surface integration can similarly be used to recover the 3D fluid moments generated about a deforming body's center of mass. We first derive a general formulation that can be applied to any body locomoting in a fluid. We then show when and how this formulation can be greatly simplified without loss of accuracy for conditions commonly encountered during fluid experiments, such as for tests done in wind or water channels. Finally, we provide detailed formulations to show how measurements from an aerodynamic force platform can be used to determine the net instantaneous moments generated by a freely flying body. These formulations also apply more generally to other fluid applications, such as underwater swimming or locomotion over water surfaces.

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On an attempt to simplify the Quartapelle–Napolitano approach to computation of hydrodynamic forces in open flows

Cited by 3 publications

References 23 publications

Application of a variational approach to the computation of forces around a wing

Application of a variational approach to the computation of forces around a wing

Load-estimation techniques for unsteady incompressible flows

Fluid moment and force measurement based on control surface integration

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