iMechanica - Comments for "Article: A new criterion for the instability threshold of a square tube bundle subject to an air-water cross-flow"
https://imechanica.org/node/26863
Comments for "Article: A new criterion for the instability threshold of a square tube bundle subject to an air-water cross-flow"enDear Romain, Thanks for your
https://imechanica.org/comment/30906#comment-30906
<a id="comment-30906"></a>
<p><em>In reply to <a href="https://imechanica.org/comment/30903#comment-30903">Dear Jinxiong,</a></em></p>
<div class="field field-name-comment-body field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p>Dear Romain, Thanks for your detailed explanation. </p>
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</ul>Tue, 26 Sep 2023 03:59:31 +0000Jinxiong Zhoucomment 30906 at https://imechanica.orgDear Jinxiong,
https://imechanica.org/comment/30903#comment-30903
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<p><em>In reply to <a href="https://imechanica.org/comment/30900#comment-30900">A very interesting work!</a></em></p>
<div class="field field-name-comment-body field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p>Dear Jinxiong,</p>
<p>Thanks very much for your interest in our work and your question.</p>
<p>From a first dimensional analysis we establish an expression of the fluidelastic instability threshold in two-phase cross-flows.</p>
<p>This threshold (see Eq. 9) is related to the single-phase instability thresholds, which therefore must be determined. </p>
<p>From a second dimensional analysis, we show that the single-phase instability threshold is a function of the Scruton number Sc, the Reynolds number Re and the Stokes number Sk. This function is expressed as a power law (see Eq. 16) of the form: Sc = a Re^b Sk^c (Connors' equation corresponding to the special case b = -c =2). The coefficients a, b and c are determined experimentally using the direct approach of Tanaka. In this approach, the tube is imposed a harmonic displacement. Measurements are performed for various flow rates, i.e. different Reynolds numbers, and different forcing frequencies, i.e. different Stokes numbers. From the measured fluid-forces, the critical Scruton number is determined. This method makes it possible to map the instability threshold by independently varying the Reynolds number and the Stokes number. Coefficients a, b and c are then extracted from experiments with the power law fit. </p>
<p>Best, </p>
<p>Romain </p>
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</ul>Thu, 21 Sep 2023 16:44:52 +0000lagrangrcomment 30903 at https://imechanica.orgA very interesting work!
https://imechanica.org/comment/30900#comment-30900
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<p><em>In reply to <a href="https://imechanica.org/node/26863">Article: A new criterion for the instability threshold of a square tube bundle subject to an air-water cross-flow</a></em></p>
<div class="field field-name-comment-body field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p>Dear Romain, I look through the paper and am impressed by the new way of obtaining fluidelastic instability thresholds via simple dimensional analysis. The single-phase equation recovers the Connors' equation widely used in engineering and academia. Just a quick question. How to determine the coefficients of the instability threshlods equation? Only via experiments?</p>
<p>Best,</p>
<p>Jinxiong</p>
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</ul>Tue, 19 Sep 2023 13:32:15 +0000Jinxiong Zhoucomment 30900 at https://imechanica.org