Abstract The paper examines the effect of acoustic excitation at broadband frequency range (100 - 650 Hz) on separated boundary layer developing a flat plate subjected to an adverse pressure gradient. experiment was conducted with low inlet turbulence intensity level (Tu < 1%) in order provide cleaner environment that magnifies effects frequency. It shown sound levels: SPL=125 and 135 dB, ca...

Laminar-turbulent transition is an important feature in aerospace aerodynamics because of its influence on fuel consumption via the drag. Despite many years of research on fundamental mechanisms of the transition process in many generic configurations relevant for aircrafts, as well as other applications, there are situations which are less well understood and hence much more difficult to predi...

The paper focuses on the investigation of unsteady effects in shock wave/boundary layer interaction. study was carried out using a flat plate model subjected to free stream Mach number 1.43 and unit Reynolds (Re1) 11.5 × 106 1/m. To generate two-dimensional disturbances laminar boundary upstream separation region, dielectric barrier discharge employed. were generated within frequency range 500 ...

Reliable estimation of the porous membranes neck-pore size distribution (NPSD) is the key element in the design and operation of all membrane separation processes. In this paper, a new approach is presented for reliable of NPSD of porous membranes using wet flow-state bubble point test data. For this purpose, a robust method based on the linear regularization theory is developed to extract NPSD...

This article discusses the enhanced lift-drag ratio of a geometrically modified National Advisory Committee for Aeronautics 0012 aerofoil at low Reynolds number 40000. The study involves validating Averaged Navier Stokes Transition Shear Stress Transport model analysis flow around subject with profile angles attack ranging from 0 to 10°. coefficient lift drag increased by 70% an angle 6°. exten...

This paper presents an investigation on the effect of introducing large-scale roughness through static curvature modifications on the low speed flow over an airfoil. The surfaces of a standard Eppler 398 airfoil have been modified with regular perturbations or “bumps” of the order of 2%c for this purpose. While the actual E398 airfoil is not a suitable candidate for low Re cases due to extensiv...

In present paper acombination of three-dimensional isothermal and two-dimensional non-isothermal Lattice Boltzmann Method have been used to simulate the motion of bubble and effect of wetting properties of the surface on bubble separation. By combining these models, three-dimensional model has been used in two-dimension for decreasing the computational cost. Firstly, it has been ensured that th...

The performance of turbomachinery blade profiles, at low Reynolds numbers, is influenced by laminar separation bubbles (LSBs). Such a bubble caused strong adverse pressure gradient (APG), and it makes the boundary layer to separate from curved profile surface, before becomes turbulent. paper consists on joint experimental numerical investigation flat plate with gradient. experiment provides det...

A large eddy simulation is performed to study secondary tones generated by a NACA0012 airfoil at angle of attack $\alpha = 3^{\circ}$ with freestream Mach number $M_{\infty} 0.3$ and Reynolds $Re 5 \times 10^4$. Laminar separation bubbles are observed over the suction side near trailing edge, on pressure side. Flow visualization spectral analysis employed investigate vortex shedding aft bubble....