2026-05-27T05:34:04Zhttps://riuma.uma.es/rest/oai/requestoai:riuma.uma.es:10630/120352026-02-03T12:05:41Zcom_10630_2254col_10630_37959
RIUMA. Repositorio Institucional de la Universidad de Málaga
author
Rodríguez-García, Jesús Óscar
author
Blanco-Rodríguez, Francisco José
author
Parras-Anguita, Luis
author
Del-Pino-Peñas, Carlos Manuel
2016-09-19T09:45:05Z
2016-09-19T09:45:05Z
2016-09-19
http://hdl.handle.net/10630/12035
http://orcid.org/0000-0002-9793-5253
Wingtip vortices represent a hazard for the stability of the following airplane in airport highways. These flows have been usually modeled as swirling jets/wakes, which are known to be highly unstable and susceptible to breakdown at high Reynolds numbers for certain flow conditions, but different to the ones present in real flying airplanes. A very recent study based on Direct Numerical Simulations (DNS) shows that a large variety of helical responses can be excited and amplified when a harmonic inlet forcing is imposed.
In this work, the optimal response of q-vortex (both axial vorticity and axial velocity can be modeled by a Gaussian profile) is studied by considering the time-harmonically forced problem with a certain frequency ω. We first reproduce Guo and Sun’s results for the Lamb-Oseen vortex (no axial flow) to validate our numerical code. In the axisymmetric case m = 0, the system response is the largest when the input frequency is null. The axial flow has a weak influence in the response for any axial velocity intensity. We also consider helical perturbations |m| = 1. These perturbations are excited through a resonance mechanism at moderate and large wavelengths as it is shown in Figure 1. In addition, Figure 2 shows that the frequency at which the optimal gain is obtained is not a continuous function of the axial wavenumber k. At smaller wavelengths, large response is excited by steady forcing. Regarding the axial flow, the unstable response is the largest when the axial velocity intensity, 1/q, is near to zero. For
perturbations with higher azimuthal wavenumbers |m| > 1, the magnitudes of the response are smaller than those for helical modes. In order to establish an alternative validation, DNS has been carried out by using a pseudospectral Fourier formulation finding a very good agreement.
eng
by-nc-nd
Mecánica de fluidos
On the optimaL response of q-vortex
conference output
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URL
https://riuma.uma.es/bitstreams/22b4de7a-522b-4d33-8387-6f88e82a8399/download
File
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8f51da658b944fb635d7b403bb26c7a0
158099
application/pdf
EUROMECH_2016_1.pdf