Pitot-static Research Articles

Design of Pitot-Static Tube Shapes and Their Influence on Airspeed Measurement Accuracy

Design of Pitot-Static Tube Shapes and Their Influence on Airspeed Measurement Accuracy

Design and Fabrication of Low-Speed Wind Tunnel (LSWT)

The design and fabrication of a low-speed wind tunnel (LSWT), which is a critical component for testing and comprehending aircraft aerodynamics, is presented in this study. Despite the increasing prominence of computational fluid dynamics (CFDs) in manufacturing engineering, wind tunnels remain essential for the intricate development of aircraft and automobile designs with complex flow interactions. Using SolidWorks, we focused on controlling flow turbulence approaching the test section, emphasizing performance and quality parameters. The construction of the wind tunnel used plywood with an axial fan regulating the airspeed, and Arduino facilitated data acquisition. The drag and lift on the Y Clerk Airfoil were quantified by two load cells along the XY-axis, complemented by a Pitot Static Tube and a multitube inclined plane manometer for pressure and velocity calculation. Fusion 360 simulation software was used to analyze pressure and velocity profiles at speeds ranging from 10 to 20 m/s, providing a comprehensive quantitative evaluation of the wind tunnel’s capabilities. By emphasizing both design innovation and quantitative performance metrics, this study underscores the continuing significance of wind tunnels in engineering.

Effect of aspect ratio on mean flow characteristics of cruciform orifice jet

PurposeThe purpose of this study reports the effects of aspect ratio (AR) on mean flow characteristics of the cruciform orifice jet.Design/methodology/approachThe aspect ratio is the height-to-width ratio of the lobe of the cruciform shape. The aspect ratios considered are 0.25, 0.5, 0.75, 1, 2, 3 and 4. The turbulent jet flow is issued through an orifice being fitted to the jet tunnel facility. The velocity measurements are recorded with the help of pitot-static tube connected to a digital manometer setup. The Reynolds number calculated using the equivalent diameter 50.46 × 10–3 m and exit velocity 51.23 m/s was 1.75 × 105. Based on the experimental data, the streamline velocity decay plots, the potential core length (PCL), mean velocity profiles and velocity half widths were plotted, and discussions were made based on the measured data. A smoke-based flow visualization was carried out at moderate Reynolds number 5396.FindingsThe PCL remains almost constant for the aspect ratio 0.25:1 and then starts decreasing for the aspect ratio 1:4. The decrease in PCL indicates improved mixing. The off-center peaks are found along the major axis in mean velocity profiles for almost all cruciform jets. More than one axis switching occurs and can be identified by the crossover points. The location of the first crossover point shifts forward, and the second crossover point shows an oscillating trend. The flow visualization exhibits the jet evolution, and the distance up to which the jet maintains the cruciform shape is increased with the aspect ratio.Research limitations/implicationsThe experiments are limited to air in air jet under isothermal conditions.Social implicationsThe cruciform orifices can be used as fuel injectors and in air-conditioning systems, thereby improving efficiency and energy usage.Originality/valueThe aspect ratio effects on PCL and axis switching are used to explain the mixing characteristics. Flow visualization was also used to support the discussion.

Exercise-induced cardiac remodelling in elite athletes is characterized by a stronger ventricular mass-volume association in females as compared with males: MRI results from the ELITE cohort

Abstract Background Differentiation between exercise-induced cardiac remodelling (EICR) and cardiac pathology constitutes a central challenge in sports cardiology. To assist clinicians, theoretical frameworks have been developed: i.e. dynamic sports are associated with ventricular dilatation, static sports with hypertrophy, and sports containing both components with both dilatation and hypertrophy. However, EICR frameworks have been almost exclusively based on findings in male athletes, and whether these associations are found in female athletes is to date unclear. Purpose We aimed to investigate intersex differences in left ventricular (LV) remodelling in the extreme phenotypes of elite athletes. Methods We included 227 healthy, elite athletes from the ELITE cohort who underwent cardiac magnetic resonance imaging (CMR). Our outcomes of interest were absolute and body surface area (BSA) indexed LV end-diastolic volume, LV end-diastolic wall mass, LV end-diastolic mass-volume ratio to express cardiac remodelling (LV end-diastolic wall mass / LV end-diastolic volume) and correlations of BSA-indexed LV mass with LV end-diastolic volume to compare LV remodelling between sexes. Results A total of 122 male and 105 female elite athletes (age 26±6 years) were included. The age and division in sports categories according to the ESC classification were similar between the sexes. Male athletes showed larger indexed LV end-diastolic volumes (127±19 versus 108±14 ml, p <0.001) and indexed LV wall mass (66±12 versus 50±11 grams, p <0.001) compared to female athletes. Male athletes had a proportionally larger LV mass-volume ratio than women (0.53±0.12 versus 0.46±0.09 g/ml, p <0.001). Female elite athletes showed a moderate association between indexed LV mass increase with indexed LV end-diastolic volume increase (Spearman’s rho 0.45, p <0.001), whereas male athletes showed a weak association (Spearman’s rho 0.25, p =0.006). Conclusions Elite male athletes have larger left ventricular volumes and wall mass, with a greater mass-volume ratio, than their female counterparts. However, female athletes demonstrate a stronger mass-volume association than males. Our findings suggest the presence of distinct sex-dependent features of EICR.

Chronotype characteristics of professional athletes in China: a comprehensive descriptive study

BackgroundChronotype has gained recognition as a significant factor in enhancing athletic performance. This study aimed to deepen our understanding of athletes’ sleep chronotypes and provide a foundation for developing evidence-based training and competition programs. By comprehensively describing and analyzing the chronotype characteristics of Chinese professional athletes, considering individual and sports factors, sleep quality and habits, and mental energy, this research aimed to contribute valuable insights to the field.MethodsA sample of 1069 professional athletes from sports teams in Shanghai completed the Athlete Sleep Screening Questionnaire and the Athlete Mental Energy Scale to assess chronotype, sleep quality, sleep-influencing habits, and mental energy.ResultsAmong athletes, sleep typology fell within the intermediate range, slightly leaning toward morningness. Male athletes and those who engaged in static sports displayed a greater propensity for morningness. Age correlated with a preference for eveningness. High-level athletes exhibited a stronger inclination toward eveningness. Sleep quality issues were associated with an inclination toward eveningness. Daily caffeine intake and the habit of using electronic devices before bedtime are also linked to eveningness. Chronotype demonstrated the ability to predict various dimensions of athletes’ mental energy. It was the strongest predictor of vigor, but the loadings were smaller than those of sleep quality.ConclusionChinese athletes’ chronotypes primarily exhibit distinct characteristics related to individual factors such as gender, sports discipline, and ranking, as well as habits like caffeine consumption and electronic device use. Moreover, these sleep patterns demonstrate predictive capabilities across all dimensions of athletes’ mental energy. This study sheds light on Chinese athletes’ unique sleep chronotype attributes, enriching our understanding of sleep patterns among professional athletes under various systems. These insights offer an initial basis for enhancing the effectiveness of athlete scheduling and training management.

Design and characterizing of blower wind tunnel using experimental and numerical simulation

A new subsonic blower wind tunnel design has been studied both numerically and experimentally; it is also referred to as “blower” wind tunnel. This paper is initially aimed to address each sequential stage of the wind tunnel design process. Rather than applying the standard method of modelling solely the flow in the test section, a large-scale CFD model of the whole wind tunnel was employed. The loss of every constituent element was calculated and then all the losses are added up to determine the power needed for the wind tunnel operation which is used as “intake fan” boundary conditions in the CFD model. Then, flow uniformity and turbulent intensity measurements in an empty test section using a pitot static tube and hot wire anemometer (HWA) were introduced to validate the CFD results. The results showed that flow quality was significantly affected by flow conditioners (uniformity devices) (honeycomb and mesh screens) in the settling chamber and wide-angle diffuser. Investigations were also conducted to evaluate the flow deficit in the wake area behind a convex hump model using both HWA and particle image velocimetry PIV. This was additional experimental tests carried out to validate the suitability of the wind tunnel designed for aerodynamic research.

Arduino Based Pressure Sensor Integration in the Measurement of Flow Field

Abstract: In fluid mechanics, study of velocity profile for a fluid flow gives better understanding about the nature and physics of fluid. We use manometer and pitot static tube in conventional way to measure the velocity profile .But advances in sensor we can use Arduino with the pressure sensor and study the velocity profile with easy and portable way. The study of velocity measurement has been done with help of sensor and electronics component

Experimental Investigation of the Flow, Noise, and Vibration Effect on the Construction and Design of Low-Speed Wind Tunnel Structure

A wind tunnel is needed for a lot of research and model testing in the field of engineering design. Commercial wind tunnels are large and expensive, making them unsuitable for small-scale aerodynamic model testing. This work aims to experimentally investigate the effects of flow, noise, and vibration on constructing and designing a low-speed wind tunnel structure. The flow uniformity in the wind tunnel has been tested by measuring the velocity profiles inside the empty test section with a pitot-static tube at various fan frequencies. The experiment results showed a good flow uniformity of more than 90% across the test section area, and the maximum wind velocity achieved was about 25.1 m/s. Due to the stability of the flow near the exit test section, the vibration measurement revealed that the entrance portion has larger vibration fluctuations than the exit part. Furthermore, as the axial fan frequency increases, the noise level increases. At 40 Hz, the noise level enters the hazardous zone, which has an impact on the person who performs the measurement process. The resonance of the wind tunnel structure is an important measurement test that affects vibration measurement.

Ram pressure in astronomy and engineering

The ram pressure of a moving fluid, P r , is the rise in pressure at a stagnation point relative to the upstream pressure. In astronomy, it is used to calculate the interaction of stellar winds with planets and to quantify the effects of ram pressure stripping. On aeroplanes and in wind tunnels, it is measured with a pitot-static tube, an inexpensive device with no moving parts that was invented in 1732. Up through the mid-1960s, across both astronomy and engineering the ram pressure of a moving gas and its momentum flux, ρ u 2 , where ρ and u are the upstream mass density and flow speed, were properly treated as related but distinct quantities. This relationship may be expressed as P r = Sp ρ u 2 , where Sp is the dimensionless Spreiter number, which ranges between 0.5 and 0.88 for a monatomic gas, depending on the upstream Mach number, Ma . Unfortunately, by the early 1970s, in astronomy ram pressure was defined to be the momentum flux and Sp was fixed to be unity and forgotten as a parameter. This article seeks to raise awareness of this issue, and to review the determination of Sp for subsonic and supersonic flow.

Pressure-velocity measurements of a small automotive fan at different working conditions. A noise generation perspective.

Although noise from large fans has been extensively studied by the scientific community, few experimental studies have been performed on small-scale fans, where aerodynamic effects due to low Reynolds numbers needs be taken into account. For this reason, some preliminary experimental investigations have been carried out on cooling fans for automotive applications. The experimental campaign has been focused on the characterization of the flow outlet first, using a static Pitot on a 5.5-inch five-bladed fan, with and without its protective grid. After this preliminary phase, simultaneous measurements of velocity with hot-wire anemometry (HWA) and pressure fluctuations with microphones have been also carried out, the HWA probe being located downstream and two microphones positioned in the nearfield and far-field of the fan. The fan has been also studied at different working conditions, varying the rotational speed and applying specific fine grids at the intake, in order to well reproduce the presence of the cooler. Analyses in the time and frequency domain have been performed on the measured data, including cross-correlation between pressure and velocity signals, in order to find the main driving mechanisms that are related to the noise generation.

Апробация опросника образных репрезентаций профессиональной деятельности спортсменов

<p>The aim of this work was to develop and test the questionnaire of imaginary representations of the professional activity of athletes. We have developed a questionnaire of 100 questions, including 9 parameters (subscales). The questionnaire was tested on 399 sportsmen, 48.4% of which were candidates for the master of sports, master of sports or international class master of sports. The statistical analysis showed a good agreement of these parameters (subscales), which was 0,61—0,89. Characteristic features of image representations (IR) were revealed for representatives of different sports. The results showed that in dynamic sports under conditions of uncertainty athletes more often note the IR of temporal, spatial, informational, energetic aspects of the sports situation, as well as the game intellect. In solitarysports athletes more often talk about motivational-personal aspects of representation, in group sports — about the representation of the social environment, which is explained by the specifics inherent in solitary and group sports activities. It is also shown that in dynamic sports under given conditions "peaks" of the profile are noted on the representation of technical-tactical, energy components and motivational-personal aspects. In static sports technical-tactical and motivational-personal aspects of representation come to the fore. Thus, the questionnaire of imaginary representations of professional activity of athletes can be used as a tool for diagnostics of peculiarities of imaginary representations in athletes.</p>

Numerička analiza pito-statičke cevi sa "aerodinamičkom korekcijom"

Numerical analysis of a flow filed around the aerodynamic compensation pitot-static tube that is used on a domestic ORAO J22 aircraft is presented in this paper. The analysis was performed for three different Mach numbers of the free stream velocity for two configurations of the pitot-static tube. The comparison of the pressure coefficient (Cp) distribution for both of the configurations is given.

Heart Rate Response and Heart Rate Recovery After Harvard Step Test Between Young High Intensity Aerobic Athletes Smokers and Non-Smokers

Background: Smoking has an influence on physiological responses and exercise performance. Exercise training results in a slow resting heart rate through changes in cardiac autonomic balance in addition to intrinsic remodeling of the sinoatrial node. Compared with athletes in static sports, heart rate is slower in athletes involved in dynamic sports. However, not many studies have examined how smoking affects the heart rate response and heart rate recovery in high-intensity aerobic athletes. Methods: This cross-sectional observational study. Data on age, gender, body mass index, smoker or non-smoker status, resting heart rate, and blood pressure before the test were collected. Maximum heart rate, heart rate 1 minute after maximum, heart rate recovery, and blood pressure after the test were measured. Data were analyzed using the SPSS version 24 program: unpaired t-test, Mann-Whitney test, ANCOVA. Results: A total of 50 samples were involved in the study, divided into 25 smoking athletes and 25 non-smoking athletes. The mean resting heart rate in smoking athletes was significantly higher (75 vs 66, p<0.001). The mean maximum heart rate was higher in smoking athletes but not statistically significant (149.5 vs 147.6, p=0.635). The mean 1-minute heart rate after the test was found to be significantly higher in smoking athletes (123 vs 112, p=0.018). The mean heart rate recovery was significantly lower in the smoking athletes (26.3 vs 35.2, p=0.002). Covariate analysis of age, gender, and body mass index did not have a simultaneous effect on resting heart rate, maximum heart rate, 1-minute heart rate after the test, and heart rate recovery (p>0.05). Conclusion: Resting heart rate and 1-minute heart rate after the Harvard Step Test were higher in young high-intensity aerobic athletes who were smokers. Heart rate recovery was lower in young high-intensity aerobic athletes who were smokers.

Control of bow shock induced three-dimensional separation using bleed through holes

The unsteady three-dimensional separated flow on a wall induced by a square protrusion (approximately twice the local boundary layer thickness in width and height), and its control by means of passive suction through holes, is investigated using wind tunnel experiments at Mach 2.87. The baseline flow without any control was characterized and compared against the cases with bleed. A bow-shaped separation line on the wall with a mid-span separation length of 5.57δ from protrusion face was traced from the oil-flow visualization. The averaged pressure distribution surveyed using static pressure ports placed on the wall has mapped plateau, high-pressure, and low-pressure regions in the separated flow, distinctive to three-dimensional interactions. Ten control configurations were tested with suction holes placed along mid-span in the different pressure regions. Significant spanwise “Mean Reduction in Separation Length” of up to 0.93δ was observed from oil-flow visualization. A comparison of observations from various control configurations suggested that bleeding the flow from the high-pressure region could delay the separation and reduce the bubble size in general. Furthermore, time-resolved Schlieren visualizations have confirmed reduction in both “mid-span separation length” and “shock-intermittent-region” with the introduction of suction in high-pressure region. Fourier and Proper Orthogonal Decomposition analysis done on the Schlieren data has confirmed the presence of low-frequency separation-shock oscillations at Strouhal Numbers of order 10−2, both with and without control. Furthermore, the amplitudes of separation-shock oscillations in the spectrum were reduced with the introduction of suction simultaneously from two holes placed in high- and low-pressure regions.

Uncertainty analysis of the air velocity standard based on LDA and wind tunnel

This paper deals with uncertainty analysis an air velocity standard consisting of a wind tunnel and a laser Doppler anemometer (LDA) measuring system. The analysis is performed for air velocities between 0.3 m/s and 40 m/s, and a calibration procedure with the readings from the LDA and the device under test (DUT) taken simultaneously. The calculation of the reference air velocity includes a systematic correction of the velocity measured by the LDA to the position of the DUT. The study provides a complete and detailed methodology for estimating all major uncertainty contributions attributed to the LDA standard, position correction including velocity field uniformity, stability and uncorrected blockage effect. The contribution of the blockage effect was estimated for three different anemometers. For the Pitot static tube, the contribution of position correction predominates; however, for the other two larger anemometers, the contribution of the uncorrected blockage effect predominates at higher velocities.

Dynamic Design CFD Simulation of Geometric Canister Gasifier Stream

Abstract: External streams in annuli are critical in regulating pressure loss, air stream distribution around the combustor liner, and the resulting impacts on performance, durability, and stability of the gas turbine combustion system. This article provides a computational fluid dynamics (CFD) simulation of the stream within a canister combustor's outer annulus. Validation of this simulation was accomplished by analysis of the stream within a canister combustor annulus utilized in a Afam/Nigeria gas turbine power plant facility. In 10 sites across the annular area, pitot static tubes were utilized to measure the velocity. By comparing the velocity profile, it was discovered that the CFD simulation and experimental work had a high degree of agreement.

Experimental and numerical studies of co-flowing jets with finite lip thickness and varying bypass ratio

ABSTRACT The study aims the effect of finite lip thickness and bypass ratio on subsonic and correctly expanded sonic co-flowing jet. The co-flowing jets characteristics were studied for two different lip thicknesses at subsonic Mach 0.6, 0.8, and sonic Mach 1.0 by varying the bypass ratio also the co-flowing jet area. The lip thickness considered for the study case is 1.0Dp and 1.5Dp (Dp – primary nozzle diameter is 10 mm). For experimental setup, the co-flowing duct area was varied the secondary inlet with 4 mm and 5 mm holes. Axial Pitot static tube survey was conducted experimentally. The numerical simulations were also carried by commercial code FLUENT- 6.3.2 for solving the RANS equations using Spalart–Allmaras turbulence model. The flow field has been visualised using numerical contours. The results indicate that for lip thickness 1.0Dp and for low bypass ratio, potential core seems to be thicker. Similar behaviour is observed in 1.5Dp lip thickness. On the other side, for both the lip thickness, 1.0Dp and1.5Dp, as the bypass ratio increases a recirculation zone occurs in the near field region and it becomes dominant. For bypass ratio 6.4 and 1.0Dp lip thickness, the recirculation zone exhibits an outer and an inner vortex.

Attention and executive control in varsity athletes engaging in strategic and static sports.

Examining non-sport-related cognitive tasks of attention and executive control in skilled athletes may provide insight into the acquisition of highly specific skills developed in experts as well as help identify successful performance in sport. Through a cross-sectional design, this study examined performance on aspects of attention and executive control among varsity athletes playing soccer (strategic sport) or track & field (static sport) using a computerized test of attention and executive control. Ninety-seven university athletes participating in soccer (n = 50) or track and field (n = 47) were included in the study. Domains of attention and executive control were examined using the Attention Network Test-Interactions (ANT-I). Mean reaction time (RT) and intra-individual variability (IIV) were compared between groups as measures of performance speed and performance stability respectively. Soccer players demonstrated overall faster RTs (p = 0.0499; ηp2 = .04) and higher response accuracy (p = .021, d = .48) on the ANT-I compared to track and field athletes. Faster RTs were observed for soccer players when presented with an alerting tone (p = .029, d = .45), valid orienting cue (p = .019, d = .49) and incongruent flanker (p = .031, d = .45). No significant group differences were observed in IIV (p = .083, d = .36). Athletes engaging in strategic sports (i.e., soccer) demonstrated faster performance under test conditions that required higher vigilance and conflict resolution. These findings suggest that engagement in strategic sports is associated with enhanced performance on non-sport-related cognitive tasks of attention and executive control.

Clinical results of dynamic tumor-tracking stereotactic body radiotherapy with real-time monitoring for liver tumors using a gimbal-mounted linac: A multi-institutional phase II study.

441 Background: Dynamic tumor-tracking (DTT) stereotactic body radiotherapy (SBRT) with real-time monitoring for liver tumors using a gimbal-mounted linac can decrease the normal liver dose and planning target volume (PTV) without sacrificing the target dose. We hypothesized that this method would yield excellent tumor control comparable to that by the conventional SBRT. We conducted a multi-institutional prospective phase II study to evaluate the safety and efficacy of DTT-SBRT for liver tumors (UMIN-CTR, UMIN000017886). Methods: The main eligibility criteria were as follows: (1) < 4 liver tumors; (2) technical difficulties with percutaneous ablation therapies, inoperable lesions, or patient refusal to undergo surgery; (3) Eastern Cooperative Oncology Group performance status of 0–2; (4) Child-Pugh score of ≤8; and (5) respiratory motion of ≥10 mm. The primary endpoint was the local control rate (LC) at 2 years (expected endpoint: > 90%), and the secondary endpoints were overall survival rate (OS), progression-free survival rate (PFS), and treatment-related toxicity. We performed DTT-SBRT with 40 Gy in 5 fractions prescribed to the PTV D95, and a maximum dose of 55−58 Gy using 7–9 static non-coplanar ports of the 6-MV beam was applied. The Kaplan-Meier analysis was performed to estimate the OS and LC. Treatment-related toxicity was scored according to the Common Terminology Criteria for Adverse Events v.4.0. Results: Forty-eight patients (48 tumors) were registered from four institutes and successfully treated between September 2015 and March 2019. Their median age was 74 years (range, 52–97). Thirty-nine tumors were hepatocellular carcinomas, and nine were metastatic liver tumors. The median tumor size was 5.8 ml (range, 0.7–64.1). At the time of data cutoff on March 31, 2021, the median follow-up period was 36.5 months (range, 3.0–62.4). The 2-year LC was 98.0%. Two-year OS and PFS were 88.8% and 55.1%, respectively. Recurrences were observed in 33 patients (68.5%). One patient (0.2%) had local recurrence, 30 (62.5%) developed new hepatic lesions outside of the irradiation field, and 9 (18.8%) had distant metastases. Grade 3 adverse events were observed in seven patients, including elevation of liver or biliary enzyme levels and hematopoietic adverse events. No treatment-related toxicity of grade 4 or higher was observed. Conclusions: Employing DTT-SBRT to treat liver tumors resulted in excellent LC with acceptable incidence of adverse events. This method will be a promising alternative therapy for patients who cannot receive surgery or percutaneous ablation therapy. To the best of our knowledge, this is the first phase II trial evaluating DTT-SBRT for liver tumors. Clinical trial information: UMIN000017886.

Effect of Angle of Attack on Pressure Distribution of NACA5520 Airfoil Blade

In this project work, experiments are carried out in low-speed subsonic wind tunnel and 30-port multitube manometer used to study the aerodynamics characteristic of cambered airfoil model NACA5520 with different velocity range and various angle of attack. Experiments were made to investigate the pressure distribution over the airfoil under velocity range from 5m/s, 10m/s, 15 m/s, and 20 m/s and various x/s locations as 0.25, 0.5, and 0.75. The pressure measurements were taken using a multi-tube manometer and pitot-static tube over the cambered airfoil at different angles of attack. Hence, the distribution of the pressure coefficient (Cp) is calculated for the different operating conditions on the tapered blade. Also, the effect of pressure distribution over the tapered blade at different velocities and AOA is studied in spanwise location of the blade.