Parametric Testing of Chevrons on Single Flow Hot Jets

Bridges, Jackie; Brown, Clifford A.

doi:10.2514/6.2004-2824

Cited by 255 publications

(240 citation statements)

References 4 publications

Supporting

Mentioning

221

Contrasting

Unclassified

Order By: Relevance

“…Nevertheless, the present results match well with RANS solutions of Engel et al [15]. Also, the profiles of axial velocities with respect to z at the lip-line match well with those of Sinha et al [13] and Bridges and Brown [1], as illustrated in Fig. 2.…”

Section: Description Of the Baseflowsupporting

confidence: 80%

“…Compared with LES and experimental data, the present simulation shows a longer potential core length and faster decay rate beyond the poten- Table 1 The flow conditions of the round and chevron jet [15], filled triangle from Xia et al [16]. The small figure shows the iso-contours ofū z at z = r 0 [13], open circle from Bridges and Brown [1] tial core. Similar deviations are also found in round jet case SMC000.…”

Section: Description Of the Baseflowmentioning

confidence: 99%

“…Here, two jets ejected from nozzles designated SMC000 (round nozzle) and SMC001 (chevron nozzle) [1] are considered in stability analysis, which has been investigated by experiments [1], Reynolds-averaged Navier-Stokes (RANS) simulations [15], and large eddy simulations [16,17]. The jets are operated at identical conditions with Mach number Ma = U j /a ∞ = 0.9, Reynolds number Re = ρ j U j D j /μ j = 1.35 × 10 6 , where a ∞ , U j , D j , μ j are far-field speed of sound, jet exit velocity, diameter, and viscosity, respectively.…”

Section: Description Of the Baseflowmentioning

confidence: 99%

“…Refs. [1,2], the influence of chevron parameters and the reduction mechanisms of dominant low-frequency noise at shallow polar angles are still poorly understood, which imposes serious problems on design and optimization of parameters of a chevron nozzle. The main evaluation methods, i.e.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Instability waves and low-frequency noise radiation in the subsonic chevron jet

Ran

Wan

et al. 2017

Acta Mech. Sin.

View full text Add to dashboard Cite

Spatial instability waves associated with lowfrequency noise radiation at shallow polar angles in the chevron jet are investigated and are compared to the round counterpart. The Reynolds-averaged Navier-Stokes equations are solved to obtain the mean flow fields, which serve as the baseflow for linear stability analysis. The chevron jet has more complicated instability waves than the round jet, where three types of instability modes are identified in the vicinity of the nozzle, corresponding to radial shear, azimuthal shear, and their integrated effect of the baseflow, respectively. The most unstable frequency of all chevron modes and round modes in both jets decrease as the axial location moves downstream. Besides, the azimuthal shear effect related modes are more unstable than radial shear effect related modes at low frequencies. Compared to a round jet, a chevron jet reduces the growth rate of the most unstable modes at downstream locations. Moreover, linearized Euler equations are employed to obtain the beam pattern of pressure generated by spatially evolving instability waves at a dominant low frequency St = 0.3, and the acoustic efficiencies of these linear wavepackets are evaluated for both jets. It is found that the acoustic efficiency of linear wavepacket is able to be reduced greatly in the chevron jet, compared to the round jet.

show abstract

Section: Description Of the Baseflowsupporting

confidence: 80%

Section: Description Of the Baseflowmentioning

confidence: 99%

Section: Description Of the Baseflowmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Instability waves and low-frequency noise radiation in the subsonic chevron jet

Ran

Wan

et al. 2017

Acta Mech. Sin.

View full text Add to dashboard Cite

show abstract

“…For example, of the above mentioned studies, Seiner et al [1] was the only group which did not employ 12 chevrons and only a single chevron configuration was investigated. Arrangement has been investigated in the past for chevrons applied to non-military style nozzles in both subsonic [9], and supersonic [10][11][12] jets. Bridges and Brown [9] found that periodic azimuthally spaced chevrons with asymmetric geometry were detrimental to subsonic noise reduction when compared to chevrons with symmetric geometry and identical penetration.…”

Section: Introductionmentioning

confidence: 99%