“…2018) is adopted to link the asynchronous data in every two orthogonal planes, inspired by the work of Dellacasagrande et al. (2021). Figure 4.( a ) Schematic of the PIV measurement planes used for reconstruction.…”
Section: Experimental Methodologymentioning
confidence: 99%
“…Notably, these intersection lines provide an opportunity to restore the global flow information from the asynchronously measured local velocity fields. Specifically, the linear stochastic estimation (LSE) method (Adrian 1994;Podvin et al 2018) is adopted to link the asynchronous data in every two orthogonal planes, inspired by the work of Dellacasagrande et al (2021).…”
Section: -D3-c Flow-field Reconstruction and Linear Stochastic Estima...mentioning
The three-dimensional flow over a low-aspect-ratio (low-
$A\!R$
) trapezoidal plate is investigated experimentally with a focus on how the tip effects impact the structure and dynamics of the separation bubble. The chord-based Reynolds number is
$5800$
, and the angle of attack varies from
$4^\circ$
to
$10^\circ$
. Once the flow separates, the separation bubble emerges and features a swallow-tailed structure that shrinks near the midspan, which is first found for the flows over low-
$A\!R$
plates. This structure develops into the conventional single-tailed structure as the angle of attack increases. Moreover, the vortex shedding within the swallow-tailed separation bubble is restored from multiple asynchronously measured local velocity fields. It is revealed that the leading-edge vortex undergoes the novel transformation from a C-shape vortex into an M-shape vortex. This vortex transformation stems from the mass transport of the near-wall spanwise flow, which affects the fluid motion on the windward side of the C-shape vortex head, strengthening and accelerating the vortex head. The strengthened vortex head facilitates the entrainment of high-momentum fluid from the outer flow. This is responsible for the formation of the swallow-tailed structure. These findings help to fill the gaps left by the downwash at low angles of attack for low-
$A\!R$
wings, and are of value in improving the cruising and gliding performance of micro-air vehicles.
“…2018) is adopted to link the asynchronous data in every two orthogonal planes, inspired by the work of Dellacasagrande et al. (2021). Figure 4.( a ) Schematic of the PIV measurement planes used for reconstruction.…”
Section: Experimental Methodologymentioning
confidence: 99%
“…Notably, these intersection lines provide an opportunity to restore the global flow information from the asynchronously measured local velocity fields. Specifically, the linear stochastic estimation (LSE) method (Adrian 1994;Podvin et al 2018) is adopted to link the asynchronous data in every two orthogonal planes, inspired by the work of Dellacasagrande et al (2021).…”
Section: -D3-c Flow-field Reconstruction and Linear Stochastic Estima...mentioning
The three-dimensional flow over a low-aspect-ratio (low-
$A\!R$
) trapezoidal plate is investigated experimentally with a focus on how the tip effects impact the structure and dynamics of the separation bubble. The chord-based Reynolds number is
$5800$
, and the angle of attack varies from
$4^\circ$
to
$10^\circ$
. Once the flow separates, the separation bubble emerges and features a swallow-tailed structure that shrinks near the midspan, which is first found for the flows over low-
$A\!R$
plates. This structure develops into the conventional single-tailed structure as the angle of attack increases. Moreover, the vortex shedding within the swallow-tailed separation bubble is restored from multiple asynchronously measured local velocity fields. It is revealed that the leading-edge vortex undergoes the novel transformation from a C-shape vortex into an M-shape vortex. This vortex transformation stems from the mass transport of the near-wall spanwise flow, which affects the fluid motion on the windward side of the C-shape vortex head, strengthening and accelerating the vortex head. The strengthened vortex head facilitates the entrainment of high-momentum fluid from the outer flow. This is responsible for the formation of the swallow-tailed structure. These findings help to fill the gaps left by the downwash at low angles of attack for low-
$A\!R$
wings, and are of value in improving the cruising and gliding performance of micro-air vehicles.
“…In this type of experiment, it is necessary to form a complete set of equipment placed around the transparent pipes, which can then be measured. This method possesses the advantages of convenient installation and simple operation because it is based on tracer particles of the pulsed laser refractive reaction flow field characteristics, making it less sensitive to outside interference; furthermore, the accuracy of PIV testing of the flow field has been thoroughly experimentally validated [14][15][16]. Therefore, the application of PIV technology in large flow metering of natural gas has the advantages of convenient installation and use, strong anti-noise ability and long service life.…”
When a PIV flowmeter is used to measure a large flow of natural gas, the flow field fluctuation and particle distribution have a significant influence on the measurement accuracy and the particle injection mode plays a key role in the flow field fluctuation and particle distribution. To improve the measurement accuracy of PIV flowmeters, the method of filling tracer particles in single pipes, multiple pipes, and L pipes of a natural gas DN100 pipeline under high-pressure working conditions was compared and analyzed through numerical calculation and testing. The results show that the disturbance distance of filling particles in L pipes was the shortest, but the particle distribution area was small, whereas the flow metering error was large. By shortening the intersection distance between the L tube injection flow field and the main flow field, the problem that the particles failed to fill the test area was effectively solved, and the peak turbulence intensity at the intersection of the flow field decreased from 13.4% to 8%. Furthermore, the optimized structure was used to measure a flow of 100–600 m3/h with different flow rates. The relative error between the flowmeter and the ultrasonic flowmeter was approximately 2%, and the metering deviation was significantly improved.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
