Experimental and numerical studies on flow from axisymmetric nozzle flow with sudden expansion for Mach 3.0 using CFD
Researches over the recent past in the field of aerodynamic vehicles have been concerned with the problem of flow separation over its base which has lead to the formation of low pressure circulation region. This pressure is found to be noticeably lower than the free stream atmospheric pressure....
| Main Authors: | , , , |
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| Format: | Conference or Workshop Item |
| Language: | English |
| Published: |
ISET 2016
2016
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/51127/ http://irep.iium.edu.my/51127/ http://irep.iium.edu.my/51127/1/51127_Experimental_and_numerical_studies.pdf |
| Summary: | Researches over the recent past in the field of aerodynamic
vehicles have been concerned with the problem of flow
separation over its base which has lead to the formation of low
pressure circulation region. This pressure is found to be
noticeably lower than the free stream atmospheric pressure.
Base drag due to such pressure differences can be up to twothirds
of the total drag and is principally dictated by base
pressure. The present study aims to conduct experiments in
order to study the variation of base pressure from an
axisymmetric nozzle exit of 10mm diameter. Area ratio i.e.
ratio of area of suddenly expanded duct to nozzle exit area
considered in this particular study is 4.84. The fundamental
control parameters considered in the study are the nozzle
pressure ratio (NPR) and length-to-diameter (L/D) ratio which
apparently are the inertia and geometric parameters
respectively. The tests are conducted for NPR’s ranging from 3
to 11 in steps of 2. Accordingly L/D ratio was considered from
10 to 1 where tests were conducted for L/D 10, 9, 8, 7, 6, 5, 4,
3, 2 and 1. The results showed that for increase in the NPR
values once the flow is attached to the duct, the base pressure
progressively decreased. Wall pressure distribution throughout
the enlarged duct is also studied to understand the oscillatory
nature of flow. This work also proposes an effective numerical
model for base pressure using Computational Fluid Dynamics
(CFD). The computational/numerical model of the
axisymmetric nozzle and the enlarged duct was constructed
using ANSYS Fluent which is the CFD solver and employed
in the present work. Numerical iterations were completed, and
the detailed values for base pressure are analyzed. The
numerical results were found to agree well with the
experimental ones. |
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