Random Aerodynamic Oddity of the Day Thread

[kach22i]

The COANDA Flow Control and Newtonian Concept Approach to Achieve Drag Reduction of Passenger Vehicle
https://www.jstor.org/stable/4473099...n_tab_contents

Abstract

In order to reduce total drag during aerodynamic optimization process of the passenger vehicle, induced drag should be minimized and pressure drag should be decreased by means of applying streamlined body shape. The reduction of wake area could decrease pressure drag, which was generated by boundary layer separation. The induced drag caused by rear axle lift and C-pillar vortex can be reduced by the employing of trunk lid edge and kick-up or an optimized rear spoiler. When a rear spoiler or kick-up shape was installed on the rear end of a sedan vehicle, drag was reduced but the wake area became larger. This contradiction cannot be explained by simply using Bernoulli's principle with equal transit or longer path theory. Newtonian explanation with COANDA effect is adopted to explain this phenomenon. The relationships among COANDA effect, down wash, C-pillar vortex, rear axle lift and induced drag are explained.

[kach22i]

Strouhal Numbers of Unsteady Flow Structures Around a Simplified Car Model
https://link.springer.com/chapter/10...642-40371-2_26

is work aims to gain relatively thorough understanding of unsteady flow structures around an Ahmed body and associated predominated Strouhal numbers St x SQ RT "A" based on the square root of the frontal area A.

[kach22i]

Flow structures in the near-wake of the Ahmed model
https://www.sciencedirect.com/scienc...89974605000514

Time-dependant analysis revealed that the shedding behind the model is analogous to vortex shedding behind bluff bodies, with most of the fluctuations confined to the axial direction.

https://www.researchgate.net/figure/...fig1_228610009

Ahmed model, dimensions in mm. Table 1: Time-averaged flow in the near-wake of the Ahmed

[freebeard]

I'm a fan of Coanda, and I see that I can make that one of six papers readable this month. Maybe I can make the time.

[kach22i]

https://www.truckinginfo.com/144119/...s?photo=176245

Trailer nose fairings help fill the gap between the tractor and trailer. Often ignored and a major source of aerodynamic drag, the nose fairings are said to be most effective in crosswind situations.

[kach22i]

Navistar Unwraps Electric Truck
October 28, 2019 • by David Cullen
https://www.truckinginfo.com/343408/...electric-truck

The eMV prototype is not only distinguished by its all-electric drive system, but by a highly swooped-down aerodynamic hood— allowed for by the removal of the MV diesel engine-- that the OEM said also boosts safety by increasing forward visibility.

[kach22i]

https://streamlinersinc.com/about-us/

Streamliners is a company formed by a team of aerospace engineers and racing experts. Our goal is to bring high performance, innovative aerodynamic products to the trucking industry.

https://streamlinersinc.com/micro-miniskirt/

Pays for itself in less than 2 month

[kach22i]

FLOWBELOW WHEEL COVERS INCLUDED ON NEW ‘MPG PACKAGE’ FOR INTERNATIONAL LT SERIES TRUCKS
Posted on November 6, 2018
FLOWBELOW WHEEL COVERS INCLUDED ON NEW ‘MPG PACKAGE’ FOR INTERNATIONAL LT SERIES TRUCKS - NextTruck Blog & Industry News - Trucker Information




https://www.flowbelow.com/aerokit


https://www.flowbelow.com/trailer-aeroslider


February 27, 2017
by James Menzies
https://www.trucknews.com/equipment/...ne/1003077466/

The AeroFender replaces standard non-aero quarter fenders and is installed on the forward-most drive wheels of the tractor. It helps direct airflow past the tractor drive wheels and also reduces road splash and spray, Butler explained.

The Trailer AeroKit mounts to the trailer suspension, combining wheel covers with patented fairings in front of, between and behind the wheels. The covers and fairings work together to deflect air around the trailer wheels and suspension. Both systems will hit the market later this year.

[kach22i]

https://www.bigmacktrucks.com/topic/...ent-with-dtna/

Posted October 13, 2016

Daimler had a Freightliner Inspiration at the IAA show with aero fenders. Unsure of the supplier.

[freebeard]

The [micro-]Miniskirt and Flowbelow look reasonable. The mudflap is a perforated plate.

That last one though, test it for tread separation events.