Emad Masroor

selected publications

1. J. Fluid Mech.

   Erratum: Streamline patterns in 2P vortex street equilibria

   Stremler, Mark A., Basu, Saikat, and Masroor, Emad

   Journal of Fluid Mechanics, 2020

   Abs HTML PDF

   Upon further examination, we have determined that the streamline patterns in figure 3 of Basu & Stremler (2017) are not shown in the co-moving frame as intended; the ide ntical error was also made in figure 4(C–F) of Basu & Stremler (2015) and figure 3.3(C–F) of Basu (2014). The vortex positions and strength ratios used in these figures do correctly correspond to equilibrium configurations that translate uniformly without relative motion, but the equations used to generate the corresponding flow patterns contained an error that resulted in streamlines being determined in a frame of reference for which the vortices move uniformly instead of remaining stationary. The equations governing passive particle motion, which were not included in these publications, are shown here for clarity.

2. arXiv

   The wake of a transversely oscillating circular cylinder in a flowing soap film at low Reynolds number

   Yang, Wenchao, Masroor, Emad, and Stremler, Mark A.

   2020

   Abs HTML PDF

   An inclined gravity-driven soap film channel was used to study the wake patterns formed behind a transversely oscillating cylinder at Re =235 \pm 14. The natural frequency of vortex shedding from a stationary cylinder, f_\textSt, was used to identify the oscillation frequencies of interest. The (dimensionless) frequency, f^*=f/f_\textSt, and amplitude, A^*=A/D, of the cylinder’s motion was varied over a large portion of the fundamental synchronization region (i.e., for f^* ≈1), and a ‘map’ of wake patterns was constructed in (f^*, A^*) space. Lock-on between the frequency of the cylinder’s motion and the dominant frequency of the resulting vortex wake was observed for a large range of this parameter space, predominantly manifested as synchronized ‘2S’ and ‘2P’ wake modes. Synchronized ‘P+S’, ‘2T’, and ‘transitional’ wakes were also found in smaller regions of parameter space. Unsynchronized ‘coalescing’ and ‘perturbed von∼\karman’ wakes were observed as the oscillation frequency became sufficiently different from f_\text_St. The wake patterns and vortex formation processes found in this study, particularly for the 2P mode wakes, are more similar to those observed by \citeWilliamson1988 in three-dimensional experiments than those found by \citeLeontini2006 in two-dimensional simulations, despite the physical constraint from the soap film that prevents three-dimensional effects in the wake.