Quiñones Rodríguez, Carlos Javier

Profile Picture

Filters

20201
Reset filters

Settings

Citations

Publication Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    Publication
    Transport phenomena in crossflow jets subject to very strong favorable pressure gradient
    (2020-12-10) Quiñones Rodríguez, Carlos Javier; Araya, Guillermo; College of Engineering; Gutierrez, Jorge Gustavo; Torres Nieves, Sheilla; Department of Mechanical Engineering; Rodriguez Abudo, Sylvia B
    Incompressible jets transversely issuing into a spatially-developing turbulent boundary layer is one of the most challenging types of three dimensional flows not only due to its fluid-dynamic complexity but also due to its technological applications; for instance, film cooling of turbine blades, chimney plumes, fuel injection, to name a few. In this investigation, an existing Direct Numerical Simulation (DNS) database of a jet in a crossflow under different streamwise pressure gradients (zero and favorable pressure gradient or sink flow, hereafter ZPG and FPG) is post-processed and analyzed. Furthermore, two different velocity ratios, VR, of the jet were prescribed in the DNS database (i.e., VR = 0.5 and 1). The temperature was regarded as a passive scalar with a Prandtl number of 0.71. The purpose is to evaluate the transport phenomena due to the interaction between the vertical jet with the incoming spatially-developing turbulent boundary layer (SDTBL) via the following mathematical and visualization tools: (i) low/high order statistics computation of flow parameters (e.g., pressure gradient, mean velocity/temperature, skin friction coefficient, Stanton number, turbulence intensities and Reynolds shear stresses), (ii) Q-criterion method, and (iii) iso-surface extraction of momentum/thermal parameters. Items (ii) and (iii) allow us to elucidate the physics behind the hydrodynamic/thermal coherent structures in crossflow jets subject to various external conditions. The analysis is performed by means of Python programming and the Paraview toolkit. The presence of a very strong FPG induces an evident damping effect on the counter-rotating vortex pair (CVP) wake development. Furthermore, a preliminary statistical analysis of the time-averaged component of the streamwise velocity, U, is carried out in unperturbed SDTBL to explore the effects of FPG (sink flow) on the logarithmic law and power law. In turbulent boundary layers subject to severe acceleration, the wake region and the well-known log region tend to merge towards a single lengthy layer under the same log slope (approx 130 wall units in length).