Global pressure measurement of transonic convex corner model with vortex generators

2022 ◽  
Author(s):  
Chao-Yu Chen ◽  
Wei-Chieh Chen ◽  
Chih-Yung Huang ◽  
Kung-Ming Chung
Aerospace ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 157
Author(s):  
Kung-Ming Chung ◽  
Kao-Chun Su ◽  
Keh-Chin Chang

Deflected control surfaces can be used as variable camber control in different flight conditions, and a convex corner resembles a simplified configuration for the upper surface. This experimental study determines the presence of passive vortex generators, VGs (counter-rotating vane type), on shock-induced boundary layer separation for transonic convex-corner flow. The mean surface pressure distributions in the presence of VGs for h/δ = 0.2 and 0.5 are similar to those for no flow control. If h/δ = 1.0 and 1.5, there is an increase in the amplitude of the mean surface pressure upstream of the corner’s apex, which corresponds to greater device drag and less downstream expansion. There is a decrease in peak pressure fluctuations as the value of h/δ increases, because there is a decrease in separation length and the frequency of shock oscillation. The effectiveness of VGs also depends on the freestream Mach number. For M = 0.89, there is an extension in the low-pressure region downstream of a convex corner, because there is greater convection and induced streamwise vorticity. VGs with h/δ ≤ 0.5 are preferred if deflected control surfaces are used to produce lift.


Aerospace ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 268
Author(s):  
Kung-Ming Chung ◽  
Kao-Chun Su ◽  
Keh-Chin Chang

A convex corner models the upper surface of a deflected flap and shock-induced boundary layer separation occurs at transonic speeds. This study uses micro-vortex generators (MVGs) for flow control. An array of MVGs (counter-rotating vane type, ramp type and co-rotating vane type) with a height of 20% of the thickness of the incoming boundary layer is installed upstream of a convex corner. The surface pressure distributions are similar regardless of the presence of MVGs. They show mild upstream expansion, a strong favorable pressure gradient near the corner’s apex and downstream compression. A corrugated surface oil flow pattern is observed in the presence of MVGs and there is an onset of compression moving downstream. The counter-rotating vane type MVGs produce a greater reduction in peak pressure fluctuations and the ramp type decreases the separation length. The presence of MVGs stabilizes the shock and shock oscillation is damped.


2013 ◽  
Author(s):  
Yuki Yamada ◽  
Masato Ishii ◽  
Takeshi Miyazaki ◽  
Hirotaka Sakaue

1988 ◽  
Vol 52 (9) ◽  
pp. 519-521
Author(s):  
NK Nordstrom ◽  
S Longenecker ◽  
HL Whitacre ◽  
FM Beck

2011 ◽  
Vol 42 (S 01) ◽  
Author(s):  
D Tibussek ◽  
F Distelmaier ◽  
S Kummer ◽  
E Mayatepek

2019 ◽  
Vol 10 (01) ◽  
pp. 33-44
Author(s):  
N.L.G. Sudaryati ◽  
I P. Sudiartawan ◽  
Dwi Mertha Adnyana

The aim of the study was to determine the effectiveness of giving hydrotherapi foot soak in hypertensive patients. The study was conducted with one group pretestposttest design without a control group by measuring blood pressure (pretest) before being given an intervention in the form of foot soak hydrotherm against 15 people with hypertension in Banjar Sri Mandala, Dauhwaru Village, Jembrana Subregency. Then do the blood pressure measurement again (posttest) after finishing the intervention. After the study was completed, the results showed that before the hydrotherapi foot bath intervention, there were 0% of patients classified as normal, 13.32% in prehypertension category, 60.08% in hypertension category I and 26.60% in hypertension category II. After the intervention was given, there were 13.32% of the patients classified as normal, 66.68% in the prehypertension category, 20.00% in the first category of hypertension and no patients belonging to the second grade hypertension category. There is a decrease of 20-30 mmHg for systolic blood pressure and 0-10 mmHg for diastolic blood pressure after intervention. Based on the results of the study it can be concluded that the hydrotherapi foot bath is effectively used to reduce blood pressure in hypertensive patients in the Banjar Sri Mandala, Dauhwaru Village, Jembrana District.


2019 ◽  
Vol 2 (3) ◽  
pp. 206-214
Author(s):  
Putri Indes Oktabriani ◽  
Fuad Ughi ◽  
Aulia Arif Iskandar

The continuous blood pressure measurement research is widely known for helpingthe development of ambulatory blood pressure monitoring where it measures blood pressureevery 15 to 30 minutes throughout the day. The cuff is a problem for the patient withAmbulatory Blood Pressure Monitor. It can make a person feel uncomfortable and must staystill when the cuff starts to inflate. It is limiting and disturbing their daily activity when thedevice is starting to measure the blood pressure. Blood pressure measurement without cuff isbeing proposed in this research, called cuff-less blood pressure measurement. It will be based onPhotoplethysmography (PPG) and Electrocardiography (ECG) signal analysis. ECG (Lead 1,Lead 2, and Lead 3) with PPG signal produced from index finger on the left hand are comparedand analyzed. Then the relation of PPG and ECG signal and the optimum location for daily usecan be obtained. The optimum location will be based on the electrode’s position that producedthe optimum ECG lead Signal to measure blood pressure. Based on the result, PPG and ECGsignal have a linear relation with Blood Pressure Measurement and Lead 1 is more stable inproducing the ECG signal. The equation from Lead 1 appeared as one of the optimum equationsfor measuring Systolic Blood Pressure (SBP) or Diastolic Blood Pressure (DBP).


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