Oscillation of shallow flow past a cavity: Resonant coupling with a gravity wave

Flow–acoustic resonance in a cavity covered by a perforated plate

“…It was observed in experiments in water channels that self-sustained oscillations, characterized by large-scale vortical structures along perforated or slotted plates with large open area ratios, would occur without acoustic or gravity wave resonance (Celik & Rockwell 2002, 2004Sever & Rockwell 2005). The coupling of such long-wavelength instability with the acoustic (Zoccola 2004) or gravity wave (Ekmekci & Rockwell 2007) resonance of a bounding cavity was also found.…”

“…Figure 8(d) shows that increasing the parameter R leads to a stabilization effect, that is, a reduction in the spatial growth rate of the unstable hydrodynamic mode. This might explain, from a homogeneous point of view, that in the previous investigations where the self-sustained oscillations occurred the cavity-backed perforated or slotted plates all had large open area ratios (around 65 %-90 %) (Celik & Rockwell 2002, 2004Zoccola 2004;Sever & Rockwell 2005;Ekmekci & Rockwell 2007). Reducing the open area ratio leads to an increase of the equivalent resistance of the perforated plate, and consequently stabilizes the flow.…”

2D experiments and numerical simulation of the oscillatory shallow flow in an open channel lateral cavity

“…Maybe one of the earliest works is the pioneering study by Kimura and Hosoda [12] where the authors measured and simulated the formation of periodic vortical structures along the opening of the cavity and their coupling with a seiche wave. Later on, Uijttewaal et al [19], Le Coz et al [20], Ekmekci and Rockwell [21], Meile et al [22], Wolfinger et al [23], Tuna et al [18], Sanjou and Nezu [24], Uijttewaal [2], Akutina [25] , Mignot et al [26], Mignot et al [27] and Perrot-Mignot et al [28] carried out a series of experimental studies which shed light on the coupling mechanisms and flow structure of these particular configurations. It must be noted that, whereas spatio-temporal velocity measurements are often found in the literature thanks to well-stablished measurement techniques such as Particle Image Velocimetry (PIV), measurements of the time evolution of the water surface are normally carried out at single points.…”

Hydrodynamic instability and sound amplification over a perforated plate backed by a cavity

“…It was first observed in experiments in water channels that long-wavelength instability along perforated and slotted plates can occur without acoustic or gravity wave resonance [21][22][23]. The coupling of this large-scale instability with the acoustic [24] and gravity wave [25] resonance of the bounding cavities was also investigated.…”