Syamir Alihan Showkat Ali
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Preferred name
Syamir Alihan Showkat Ali
Official Name
Syamir Alihan, Showkat Ali
Alternative Name
Alihan Showkat Ali, Syamir
Showkat Ali, Syamir A.
Ali, Syamir Alihan Showkat
Showkat Ali, S.A
Showkat Ali, Syainir Alihan
Main Affiliation
Scopus Author ID
57190746528

Research Output
Now showing 1 - 2 of 2
  • Publication
    Control of flows around bluff bodies mediated by porous materials
    ( 2020-06-01)
    Sadeghipour, Sakineh
    ;
    Syamir Alihan Showkat Ali
    ;
    Liu, Xiao
    ;
    Azarpeyvand, Mahdi
    ;
    Thorpe, Graham R.
    There is evidence that the application of porous media to the surfaces of bluff bodies immersed in turbulent fluid flows has a profound effect on the associated aerodynamic phenomena. This idea is explored by performing a series of experiments on cylinders that have circular, square and rectangular cross sections. The flow fields were established around circular cylinders that had been encased in porous media, and which retained the same dimensions of the bare cylinder. The square and rectangular bluff bodies were modified so that their upstream and downstream halves consisted of solid and porous materials respectively. It is found that the porous media applied to the circular cylinder had the most effect on the wake, and the largest effect was observed in the wake generated by the most permeable material. The principal effect of the porous media was to cause the eyes of the recirculation region to be located further downstream. The effect of the permeability is increasingly diminished in the square and rectangular geometries. The presence of the porous media also had a significant effect on the Reynolds stresses. The effect of the porous media applied is to damp the normal stresses further downstream of the bluff bodies.
      2  2
  • Publication
    Trailing edge bluntness noise reduction using porous treatments
    ( 2020-05-26)
    Syamir Alihan Showkat Ali
    ;
    Azarpeyvand, Mahdi
    ;
    Ilário da Silva, Carlos R.
    This paper provides an experimental investigation of the noise generated from a blunt flat plate and the possibility of the control of noise at source using porous trailing edges. The noise generation characteristics have been examined using a flat plate equipped with surface pressure transducers and far-field microphones and was performed in an anechoic open jet wind tunnel. Two types of porous materials with different porosities and permeability constants were tested. Simultaneous near-field and far-field noise measurements, as well as the boundary layer and wake flow measurements, have been carried out to better understand the effects of the porous treatment to the flow-field and the noise generation mechanism of the plate. Results have shown that the use of porous trailing edges can generally lead to the effective suppression of both the tonal noise, due to the vortex shedding from the blunt trailing edge and also the broadband noise of the plate. The level of the noise reduction was also found to be dependent on the porosity and permeability of the porous materials. The directivity patterns of the radiated noise have shown significant noise reduction at the vortex shedding frequencies. The flow measurement results have shown that the use of porous trailing edges leads to the reduction of flow acceleration over the blunt edges, and subsequently the delay and weakening of the vortex shedding. The results presented in this paper provide an impetus for further experimental and numerical studies on the use of porous treatments for the suppression of aerodynamically generated noise at source.
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