“…It was usually assumed that the force coefficients approach constant values at high Reynolds number. The recent research reported by Mahon and Meskell (2012) and in the present work, however, indicates that the effect of Reynolds number on the lift coefficient in the rotated triangular tube array may not be ignored. Charreton et al (2015) found that the lift coefficient is sensitive to the tube array pattern, pitch ratio and Reynolds number.…”
Section: Chapter 4 Investigation Of Reynolds Number Effect On Force Ccontrasting
Tube arrays in industrial components such as heat exchangers and steam generators are susceptible to damage due to fluidelastic instability (FEI). This study focuses on the modelling of fluidelastic instability in tube arrays subjected to cross-flow. There is agreement on the idea of introducing a time delay in FEI models. Although it is one of the key parameters for FEI models, the phenomenon behind this time delay is still subject to many possible explanations, and the underlying physics is still not well understood.In the present work a new time delay formulation for the class of the quasi-steady FEI models is derived in the frequency domain in the form of an Equivalent Theodorsen Function.Unsteady and quasi-static fluid forces were measured to develop the time delay formulation.The effect of Reynolds number on the static force coefficients was also investigated. The time delay function was found to be also dependent on the Reynolds number which implies that the fluidelastic instability is also Reynolds number dependent. Comparison to other time delay functions proposed in the quasi-steady and quasi-unsteady models is made. An initial overshoot in the lift force was observed for the present model.
“…It was usually assumed that the force coefficients approach constant values at high Reynolds number. The recent research reported by Mahon and Meskell (2012) and in the present work, however, indicates that the effect of Reynolds number on the lift coefficient in the rotated triangular tube array may not be ignored. Charreton et al (2015) found that the lift coefficient is sensitive to the tube array pattern, pitch ratio and Reynolds number.…”
Section: Chapter 4 Investigation Of Reynolds Number Effect On Force Ccontrasting
Tube arrays in industrial components such as heat exchangers and steam generators are susceptible to damage due to fluidelastic instability (FEI). This study focuses on the modelling of fluidelastic instability in tube arrays subjected to cross-flow. There is agreement on the idea of introducing a time delay in FEI models. Although it is one of the key parameters for FEI models, the phenomenon behind this time delay is still subject to many possible explanations, and the underlying physics is still not well understood.In the present work a new time delay formulation for the class of the quasi-steady FEI models is derived in the frequency domain in the form of an Equivalent Theodorsen Function.Unsteady and quasi-static fluid forces were measured to develop the time delay formulation.The effect of Reynolds number on the static force coefficients was also investigated. The time delay function was found to be also dependent on the Reynolds number which implies that the fluidelastic instability is also Reynolds number dependent. Comparison to other time delay functions proposed in the quasi-steady and quasi-unsteady models is made. An initial overshoot in the lift force was observed for the present model.
“…Indeed, the values they found seem reasonable and compared well with Mahon and Meskell (2012), see Table 1. Furthermore, the value of 1.2 for C L;y found by potential theory and shown in Fig.…”
Section: Stability Of a Single Tube With The Quasi-steady Modelsupporting
confidence: 70%
“…It should also be emphasized that C L;y crossing zero has also been observed by Mahon and Meskell (2012) at high Reynolds numbers for P=D ¼ 1:375, and in two-phase flow by Sawadogo and Mureithi (2015b) at around 5% void fraction. They addressed this point, emphasizing that FEI has been observed at this point experimentally.…”
Section: Stability Of a Single Tube With The Quasi-steady Modelmentioning
confidence: 77%
“…Price and Païdoussis (1984) measured a value of À243 for a different pitch ratio (1.375) for the middle cylinder in the 5th row. In a wind tunnel, Mahon and Meskell (2012) found values ranging from À 3.2 to 0.2 for the pitch Reynolds numbers varying between 2 Â 10 4 and 9.8 Â 10 4 . There is an obvious scatter in the data.…”
Section: Post-processing Methodsmentioning
confidence: 97%
“…Some techniques can be used to lower the experimental uncertainty: averaging the noise or e.g. applying a pseudo-modal decomposition for bi-stable flows in Mahon and Meskell (2012). These measurement techniques can have an impact and lead to different results.…”
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