Papers by Mehmet Çalişkan
Radiation and power flow characteristics of plate-like structures which constitute the bodies of ... more Radiation and power flow characteristics of plate-like structures which constitute the bodies of the well-known engineering applications like cars and household appliances is a primary research field in vibroacoustics. In this study, representative radiation characteristics of plates is examined on the surface of a 300 mm x 300 mm steel square plate excited by a shaker at its midpoint. Two-microphone sound intensity measurement with a probe utilizing side-by-side configuration is used to analyze the near-field radiation characteristics. Surface intensity is simultaneously measured on the plate with another probe consisting of a condenser microphone and an eddycurrent non-contact displacement transducer to compare the results with the twomicrophone sound intensity measurement. Structural intensity technique is utilized for visualization of the power flow throughout the plate's surface. Sound power levels and radiation efficiencies are determined by these two acoustical methods and results are compared with those obtained from an analytical model of the radiating plate. In this particular model, the plate is modeled by a collection of small baffled pistons with equal areas functioning in their own true phases. It is also shown that both experimental methods yield reasonably close results, at especially low frequencies, and analytical results obtained from the model display a similar trend with the experimental results.
Near field radiation behavior of a free-free, lightly damped square plate, which is excited at it... more Near field radiation behavior of a free-free, lightly damped square plate, which is excited at its midpoint, is analytically and experimentally studied. First, the plate is computationally discretized into equal segments that are replaced by simple, phase-correlated acoustic sources. Piston radiator models (with and without mutual radiation impedance terms) are examined along with the pulsating sphere model. The radiated power from phase-correlated discrete sources is calculated; their individual phases are obtained from the surface vibration measurements.
This paper presents a new design of quarter wave tube (QWT) geometry to be utilized in the engine... more This paper presents a new design of quarter wave tube (QWT) geometry to be utilized in the engine air intake system for attenuating noise at a low frequency in the absence of mean flow. For a specified given free space within the intake system, geometrical parameters are adjusted to accommodate a compact folded tube with baffles inside. Such compactness techniques increase the acoustic energy loss in the tube accompanied with reduction in transmission loss performance. Commercial acoustic finite element software was used to numerically predict transmission loss of the proposed quarter wave tube and its corresponding simple straight-side branch counterpart. Effects of cross sectional area, tube folding and inclusion of baffles on its transmission loss performance have been investigated. It is demonstrated that an optimization between compactness and transmission loss performance can be attained with respect to frequency of desired attenuation. a
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Papers by Mehmet Çalişkan