scholarly journals Studies on Flows Development in a Suddenly Expanded Circular Duct at Supersonic Mach Numbers

2021 ◽  
Vol 39 (1) ◽  
pp. 185-194
Author(s):  
Abdul Aabid ◽  
Sher Afghan Khan
Keyword(s):  
Flow Field ◽  
Pressure Distribution ◽  
Wall Pressure ◽  
Circular Duct ◽  
Flow Development ◽  
Duct Wall ◽  
Mach Numbers

This article focuses on the flow development and the static wall pressure distribution along the circular duct from the convergent-divergent (CD) nozzle. The study aims to examine the quality of the stream in the conduit when the control is employed. The microjets are activated at the base at (PCD) of 13 mm, and the diameter of the microjets is 1 mm. Mach numbers of the investigation are 1.3, 1.9, and 2.4. The length of the duct considered was from L = 10D to 1D. The diameter of the enlarged tube was 16 mm. The experiments were conducted for NPRs from 3 to 11. The results revealed that the lowest duct length mandatory for the flow continued to attach with the circular duct wall are L/D = 1, 2, and 3 for Mach numbers 1.3, 1.9, and 2.4, respectively. The investigation outcome indicates that there are mild oscillations in the flow-field for correctly expanded flows. The oscillatory trend has a pronounced impact on the duct's flow when the jets are operated at higher NPRs. The control does not adversely affect the flow field, and the magnitude of wall pressure is nearly similar.

scholarly journals Experimental Research of Wall Pressure Distribution and Effect of Micro Jet at Mach 1.5

2019 ◽  
Vol 8 (2S3) ◽  
pp. 1000-1003 ◽  
Keyword(s):  
Adverse Effect ◽  
Flow Field ◽  
Pressure Distribution ◽  
Area Ratio ◽  
Wall Pressure ◽  
Rapid Expansion ◽  
Base Region ◽  
Active Controls ◽  
Circle Diameter

In this paper, a study on the effect of the control on the wall pressure as well as the quality of the flow when tiny jets were employed. The small jet aimed to regulate the base pressure at the base region of the suddenly expanded duct and wall pressure distribution is carried out experimentally. The convergent-divergent (CD) nozzle with a suddenly expanded duct was designed to observe the wall pressure distribution with and without control using small jets. In order to obtain the results with the effect of controlled four tiny jets of 1 mm diameter located at a ninety-degree interval along a pitch circle diameter (PCD) of 1.3 times the CD nozzle exit diameter in the base, region was employed as active controls. The Mach numbers of the rapidly expanded are 1.5. The jets were expanded quickly into an axis-symmetry duct with an area ratio of 4.84. The length-todiameter (L/D) ratio of the rapid expansion duct was diverse from 10 to 1. There is no adverse effect due to the presence of the tiny jets on the flow field as well as the quality of the flow in the duct

scholarly journals Active Control of Wall Pressure Flow Field at Low Supersonic Mach Numbers

2016 ◽  
Vol 16 (053) ◽  
pp. 90-98 ◽  
Author(s):  
Mohammed Asad Ullah ◽  
Musavir Bashir ◽  
Ayub Janvekar ◽  
S. A. Khan
Keyword(s):  
Flow Field ◽  
Active Control ◽  
Wall Pressure ◽  
Pressure Flow ◽  
Mach Numbers

Impact of expansion level on flow field of a circular duct at high Mach numbers

2021 ◽  
Author(s):  
Sher Afghan Khan ◽  
Zakir Ilahi Chaudhary ◽  
Maughal Ahmed Ali Baig ◽  
Ridwan ◽  
Hamza Afser Delvi ◽  
...  
Keyword(s):  
Flow Field ◽  
Circular Duct ◽  
Expansion Level ◽  
Mach Numbers ◽  
High Mach

Experiments on wall pressure at area ratio 4.84 in a suddenly expanded flow field at supersonic Mach numbers

2022 ◽  
Author(s):  
Sher Afghan Khan ◽  
Zakir Ilahi Chaudhary ◽  
Maughal Ahmed Ali Baig ◽  
Ridwan ◽  
K. M. Chethan ◽  
...  
Keyword(s):  
Flow Field ◽  
Area Ratio ◽  
Wall Pressure ◽  
Mach Numbers

scholarly journals Effects of Micro jets on the Flow Field of the Duct with Sudden Expansion

2019 ◽  
Vol 8 (9S2) ◽  
pp. 636-640 ◽  
Keyword(s):  
Mach Number ◽  
Flow Field ◽  
Pressure Distribution ◽  
Pressure Ratio ◽  
Wall Pressure ◽  
Base Pressure ◽  
Sudden Expansion ◽  
Orifice Diameter ◽  
Nozzle Pressure ◽  
Circle Diameter

This paper presents the results of an experimental investigation to study the effectiveness of the control jets to control base pressure in rapidly expanded circular tubes. Four tiny jets of 1 mm orifice diameter located at ninety degrees interval in cross shape along a pitch circle diameter of 1.3. The Mach number, the L/D ratio, and the area ratio of the study were 2.8, from 1 to 10, and 4.84, respectively. The nature of the flow field, the development of the flow in the duct, as well as the static wall pressure distribution in the duct was measured and discussed. The results indicate that the tiny jets can be used as an active dynamic controller for the base pressure. The wall pressure distribution is not adversely influenced by the small jets. From the present investigation, it is evident that for a given Mach number and nozzle pressure ratio one can identify the minimum duct L/D needed for the flow remained attached with the wall of the duct. The trend for the duct length L = 5D seems to show different results, due to the influence of back pressure and the peak pressure values are also less than that those were for higher L/D ratios, especially in respect of L/D = 5. Further, the flow field has smoothened in the duct, and wall pressure values with and without micro jets are identical. This trend continues until L/D = 4, then later for lower L/Ds like L/D = 3, the flow seems to be attached at higher NPRs. But for lower NPRs the flow is not attached

scholarly journals Experimental Research on Wall Pressure Distribution in C-D Nozzle at Mach number 1.1 for Area Ratio 3.24

2019 ◽  
Vol 8 (2S3) ◽  
pp. 971-975 ◽  
Keyword(s):  
Experimental Investigation ◽  
Mach Number ◽  
Flow Field ◽  
Pressure Distribution ◽  
Pressure Ratio ◽  
Area Ratio ◽  
Wall Pressure ◽  
Circulation Zone ◽  
Nozzle Pressure Ratio ◽  
Nozzle Pressure

In this experimental investigation the work reported is about the influence of control on the flow field in the suddenly expanded duct at low supersonic Mach number. A Convergent-divergent (CD) nozzle was designed and fabricated out of brass material assembled with the suddenly expanded duct which was also made of brass material. At the re-circulation zone, the flow field was controlled by using the micro jets of 1 mm diameter as an orifice and the control was arranged at an interval of 90 degrees at 6.5 mm from the central axis of the main jet. The measured wall pressure distribution was presented for Mach number 1.1 for the duct diameter of 18 mm leading to the area ratio 3.24. The L/D ratio of the duct was varied from 1 to 10, and the nozzle pressure ratio (NPR) considered for the experiments was from 3, 5, 7, 9 and 11. The present results have demonstrated that the micro jets do not influence the flow field in the duct adversely and the flow field remained identical in the presence of control or absence of control

scholarly journals Experimental Research on Flow Development and Control Effectiveness in the Duct at High Speed

2019 ◽  
Vol 8 (2S8) ◽  
pp. 1763-1768
Keyword(s):  
High Speed ◽  
Recirculation Zone ◽  
Control Mechanism ◽  
Circular Duct ◽  
Control Effectiveness ◽  
Flow Development ◽  
Expansion Level ◽  
Inertia Parameters ◽  
And Control

This paper presents an experimental study of suddenly expanded flows at supersonic speed is performed. A Convergent-divergent (C-D) nozzle is used with suddenly expanded duct. At the recirculation zone, the pressure is controlled by using four microjets of 1 mm diameter arranged at PCD of 1.3 as an active control mechanism to regulate the pressure in the wake region. The development and the quality of the flow were monitored to ensure that the flow control does not aggravate the flow field in the duct. The geometrical and the inertia parameters are the area ratio and the Mach number. The area of the study was 3.24, L/D ratio was from 10 to 1, and the level of inertia as 2.1. The expansion level considered during the experiments was from 3 to 11. The results clearly indicate that the wall pressure variation with and without control in the enlarged duct does not vary, which means that the use of control does not affect the flow filed in the circular duct.

scholarly journals Control of CD Nozzle Flow using Microjets at Mach 2.1

2019 ◽  
Vol 8 (9S2) ◽  
pp. 631-635 ◽  
Keyword(s):  
Wind Tunnel ◽  
Flow Field ◽  
Pressure Distribution ◽  
Active Control ◽  
Control Mechanism ◽  
Area Ratio ◽  
Wall Pressure ◽  
Orifice Diameter ◽  
Nozzle Flow ◽  
Circle Diameter

This paper reports the outcome of the wind tunnel investigation performed to study the effectiveness of the control jets to regulate the base pressure in an abruptly expanded circular pipe. Tiny jets four in a number, of 1 mm orifice diameter located at ninety degrees in cross shape along a pitch circle diameter (PCD) of 1.3 as a control mechanism were employed. The Mach numbers and the area ratio of the study were 2.1, and 4.84. The length-to-diameter (L/D) ratio of the duct tested was varied from 10 to 1. Nature of the flow in the duct, as well as static wall pressure distribution in the suddenly enlarged duct, was recorded. The main aim of this study was to assess the influence of the active control in the form of tiny jets on the flow field as well as the nature of the flow, and also the development of the flow in the duct. The results obtained in this study show that the flow field, as well as the wall pressure distribution, is not adversely influenced by the tiny jets. The minimum duct length seems to be 2D for NPR's in the range five and above. However, for all the level of expansion of the present study, the minimum duct length needed for the flow to remain attached seems to be 3D

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