Investigations of unsteady aerodynamic effects generated by heave and pitch motion in different vehicle body shapes with model excitation tests

In this study, unsteady aerodynamic forces induced by forced pitch and heave motions are measured and formulated to the unsteady aerodynamic coefficients by utilizing the 1/4-scale nearly actual vehicle model with wheels and wheel-houses and a system without unnecessary stings exposed to the flow. T...

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Autores principales:	Kazuhiro MAEDA, Daisuke TSUBAKINO, Susumu HARA, Akihiro SASOH
Formato:	article
Lenguaje:	EN
Publicado:	The Japan Society of Mechanical Engineers 2020
Materias:	aerodynamics unsteady flow road vehicle wind tunnel unsteady aerodynamic force response function Mechanical engineering and machinery TJ1-1570
Acceso en línea:	https://doaj.org/article/749a216060334d9aadd9da4518a83111
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spelling	oai:doaj.org-article:749a216060334d9aadd9da4518a831112021-11-29T06:01:26ZInvestigations of unsteady aerodynamic effects generated by heave and pitch motion in different vehicle body shapes with model excitation tests2187-974510.1299/mej.20-00276https://doaj.org/article/749a216060334d9aadd9da4518a831112020-09-01T00:00:00Zhttps://www.jstage.jst.go.jp/article/mej/7/5/7_20-00276/_pdf/-char/enhttps://doaj.org/toc/2187-9745In this study, unsteady aerodynamic forces induced by forced pitch and heave motions are measured and formulated to the unsteady aerodynamic coefficients by utilizing the 1/4-scale nearly actual vehicle model with wheels and wheel-houses and a system without unnecessary stings exposed to the flow. The unsteady aerodynamic lift forces are measured as input forces at front and rear axles in vehicle suspensions for each, and are expressed as the aerodynamic inerter, aerodynamic damping and aerodynamic spring coefficients which are equivalent in vehicle suspension property. These studies are conducted with less than 1.4 × 106 of Reynolds number and with less than 0.2 of non-dimensional frequency. From the results, it is observed the effect of front aerodynamic forces in proportion to motion acceleration which works as an inerter can be ignored in both of pitch and heave motion, but the effect of rear aerodynamic forces as an inerter must be considered in both motion, and the first-order lag must be considered additionally about the rear only in heave motion. Furthermore, the large difference of unsteady aerodynamic characteristics is obtained while comparing in different vehicle body shapes which are without and with a protrusion on the roof. Especially, the difference of unsteady aerodynamic forces of rear in pitch motion is much large. In the case without the protrusion, the aerodynamic inerter which restrains pitch motion is occurred. On the other hand, in the case with the protrusion, the effect of aerodynamic inerter decreases and other aerodynamic forces promotes pitch motion in opposite. The phenomenon of this difference is closely related to the behavior of flow velocities at near surface around the model. From the above, it is confirmed that the large difference of unsteady aerodynamic forces induced by motions occurs in the detail difference of body shapes at a nearly actual vehicle model, and can be expressed quantitatively as the difference of aerodynamic response.Kazuhiro MAEDADaisuke TSUBAKINOSusumu HARAAkihiro SASOHThe Japan Society of Mechanical Engineersarticleaerodynamicsunsteady flowroad vehiclewind tunnelunsteady aerodynamic forceresponse functionMechanical engineering and machineryTJ1-1570ENMechanical Engineering Journal, Vol 7, Iss 5, Pp 20-00276-20-00276 (2020)
institution	DOAJ
collection	DOAJ
language	EN
topic	aerodynamics unsteady flow road vehicle wind tunnel unsteady aerodynamic force response function Mechanical engineering and machinery TJ1-1570
spellingShingle	aerodynamics unsteady flow road vehicle wind tunnel unsteady aerodynamic force response function Mechanical engineering and machinery TJ1-1570 Kazuhiro MAEDA Daisuke TSUBAKINO Susumu HARA Akihiro SASOH Investigations of unsteady aerodynamic effects generated by heave and pitch motion in different vehicle body shapes with model excitation tests
description	In this study, unsteady aerodynamic forces induced by forced pitch and heave motions are measured and formulated to the unsteady aerodynamic coefficients by utilizing the 1/4-scale nearly actual vehicle model with wheels and wheel-houses and a system without unnecessary stings exposed to the flow. The unsteady aerodynamic lift forces are measured as input forces at front and rear axles in vehicle suspensions for each, and are expressed as the aerodynamic inerter, aerodynamic damping and aerodynamic spring coefficients which are equivalent in vehicle suspension property. These studies are conducted with less than 1.4 × 106 of Reynolds number and with less than 0.2 of non-dimensional frequency. From the results, it is observed the effect of front aerodynamic forces in proportion to motion acceleration which works as an inerter can be ignored in both of pitch and heave motion, but the effect of rear aerodynamic forces as an inerter must be considered in both motion, and the first-order lag must be considered additionally about the rear only in heave motion. Furthermore, the large difference of unsteady aerodynamic characteristics is obtained while comparing in different vehicle body shapes which are without and with a protrusion on the roof. Especially, the difference of unsteady aerodynamic forces of rear in pitch motion is much large. In the case without the protrusion, the aerodynamic inerter which restrains pitch motion is occurred. On the other hand, in the case with the protrusion, the effect of aerodynamic inerter decreases and other aerodynamic forces promotes pitch motion in opposite. The phenomenon of this difference is closely related to the behavior of flow velocities at near surface around the model. From the above, it is confirmed that the large difference of unsteady aerodynamic forces induced by motions occurs in the detail difference of body shapes at a nearly actual vehicle model, and can be expressed quantitatively as the difference of aerodynamic response.
format	article
author	Kazuhiro MAEDA Daisuke TSUBAKINO Susumu HARA Akihiro SASOH
author_facet	Kazuhiro MAEDA Daisuke TSUBAKINO Susumu HARA Akihiro SASOH
author_sort	Kazuhiro MAEDA
title	Investigations of unsteady aerodynamic effects generated by heave and pitch motion in different vehicle body shapes with model excitation tests
title_short	Investigations of unsteady aerodynamic effects generated by heave and pitch motion in different vehicle body shapes with model excitation tests
title_full	Investigations of unsteady aerodynamic effects generated by heave and pitch motion in different vehicle body shapes with model excitation tests
title_fullStr	Investigations of unsteady aerodynamic effects generated by heave and pitch motion in different vehicle body shapes with model excitation tests
title_full_unstemmed	Investigations of unsteady aerodynamic effects generated by heave and pitch motion in different vehicle body shapes with model excitation tests
title_sort	investigations of unsteady aerodynamic effects generated by heave and pitch motion in different vehicle body shapes with model excitation tests
publisher	The Japan Society of Mechanical Engineers
publishDate	2020
url	https://doaj.org/article/749a216060334d9aadd9da4518a83111
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Investigations of unsteady aerodynamic effects generated by heave and pitch motion in different vehicle body shapes with model excitation tests

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