Accession Number:

AD1113364

Title:

Large-Eddy Simulations of Nozzle-Exit Conditions in Subsonic Jet Flows

Descriptive Note:

[Technical Report, Memorandum Report]

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s):

Report Date:

2020-10-26

Pagination or Media Count:

25

Abstract:

Large-eddy simulations have been used to simulate the nozzle-exit conditions of subsonic jet flows generated by three types of nozzles. The wall-model approach is used to account for the nozzle boundary-layer effect. The nozzles involved in this study are all related to the SMC000nozzle tested extensively at NASA Glenn Research center. The nozzle-exit profiles are comparable to those measured in experiments using the similar nozzle geometries. To investigate the boundary-layer state on the nozzle-exit conditions, pipe extensions are attached to the SMC000 nozzle to generate nozzle-exit boundary layers in laminar, transitional and turbulent states. It is found that the downstream jet plume affects the nozzle-exit boundary-layer development, causing the boundary-layer transition occurs earlier than that observed inside a pipe. The nozzle-exit boundary layers in the transitional state involve significantly larger turbulence intensities, similar to those observed in highly disturbed but nominally laminar boundary layers shown in experiments. This may indicate that those highly disturbed nominally laminar boundary layers are in the transitional state.

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

[A, Approved For Public Release]