In regard to the problem of aircraft noise mitigation, the present study focuses on the refraction effects to be possibly induced by anechoic facility jet flows on the measured acoustic signatures, during typical airframe noise experiments. To this end, Computational AeroAcoustics (CAA) calculations based on the solving of the Perturbed Euler Equations (PEE) are conducted, enabling the estimati...

[1] The seasonal cycle of the near-surface circulation off central Chile was analyzed using satellite altimetry and an oceanic model. To evaluate the role of the wind stress curl on the circulation we performed two identical simulations except for the wind-forcing: the “control run” used long-term monthly mean wind stress and the “no-curl run” used a similar wind stress field, but without curl....

High intensity acoustic radiation occurs when turbulence convects past airframe trailing edges. A mathematical model is developed to predict this acoustic radiation. The model is dependent on the local flow and turbulent statistics above the trailing edge of the flight vehicle airframe. These quantities are dependent on the jet and flight vehicle Mach numbers and jet temperature. A term in the ...

Jet vortex generators have been proven to provide a mechanism to positively control boundary layer flows. The present paper illustrates a method to perform direct numerical simulations (DNS) of a jet actuator flow inside a laminar boundary layer. A structured finite difference method is used for the simulations. The numerical scheme was adapted to account for the large scale differences both in...

In this paper the flow field of a rectangular synthetic jet driven by a piezoelectric membrane issuing into a quiescent environment is studied. The similarities exhibited by synthetic and continuous turbulent jets lead to the hypothesis that a rectangular synthetic jet within a limited region downstream of the orifice be modeled using similarity analysis just as a continuous planar jet. Accordi...

In this paper we use the predicted spatial development of helical structures along an expanding jet to model observed structures and motions in the 3C 120 jet. New results of VLBI imaging of the parsec-scale radio jet in 3C 120 at 5 GHz are examined along with older long term monitoring results at 5 GHz and older results obtained at 22 and 43 GHz. The high frequency observations provide detaile...

This study examines the single-phase and two-phase cooling performance of a hybrid micro-channel/micro-jet impingement cooling scheme using HFE 7100 as working fluid. This scheme consists of supplying coolant from a series of jets that deposit liquid into the micro-channels. A single-phase numerical scheme that utilizes the k–e turbulent model and a method for determining the extent of the lami...

Accidental release scenarios such as flammable gas leaks or ruptures of pipes and pressurised process-equipment normally originate high velocity jets which, if ignited, give rise to jet fires. Although the direct effects of jet fires are considered to be relatively smaller than that associated to other types of fires, they are characterized by high heat fluxes and, especially if there is flame ...

We present a methodology for the computation of flow fields involving complex perforated surfaces in propulsion applications. Of particular interest is the treatment of perforated flaps used as wedge-shaped fan flow deflectors for reducing jet noise of a supersonic turbofan engine. A three-dimensional Reynolds-Averaged Navier-Stokes solver is used to compute the flow field of the external jet p...

Measurements were made of the flow field structure and the near field parameters of a jet exhausting from a sonic nozzle with a 1.27 cm exit diameter. Compressed air was used for obtaining stagnation pressures up to ~ 5 atmospheres. The jet exhausted vertically from a settling chamber into an acoustically insulated room and through an insulated duct out through the roof. Measurements were made ...