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USE OF VORTEX GENERATORS TOELIMINATE SNOW AND SAND DRIFTING ON
WASHINGTON STATE HIGHWAYS
Mike Stanford, Washington State Department of Transportation, Avalanche ControlNorth Central Region.
2393 Kinnikinnick DR.Leavenworth WA 98826
(509) 664-1257
Site # 1 Mansfield, Washington.
Abstract
Site # 2 Vantage, Washington
Drifting snow and sand on state highways hasbeen a problem for travelers and state workersfor as long as there have been roads. Thispresentation will describe an experimentunderway in North Central Washington to see ifthe Vortex Generators*'can passively removedrifting snow and sand from the road. As statefunds for maintenance are continually beingreduced, more cost effective ways are needed toke~p c~rtain sections of highways safe and opendunng Inclement weather periods.
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Two eight-foot Generators were placed near aspecific section of roadway during the winter of1999-2000. This area receives snowdrifts thatare a continuous problem.During the summer of 2000, three wings wereplaced at a location where sand from the dunesalong the Columbia River blow sand onto theroadway causing an extreme safety hazard formotorist.This presentation is intended as an overview ofthe ongoing project.
Introduction
We were first made aware of the VortexGenerator while attending the ISSW in 1998.Renee Lang (Sigma Technologies Inc.) had donesome work in Antarctica moving snow around tokeep a runway open. The idea came to us thatmaybe this would work in spots along severalhighways in Washington State where we havesevere drifting problems. At times, drifting is sobad that a whole community can be shut off fromvital services for days at a time. After talking toRenee on several occasions during and after theconference, we became very excited abouttesting a wing to see if our hypothesis would becorrect.As luck would have it, our desire to test a newproduct had come at the same time the voters ofWashington State passed an initiative that cutour research and development budget down tozero. Money was tight, however the desire totest a wing and the possible savings to the sate ifit worked, kept us motivated to make it happen.
Questions Questions Questions
The ball was set into motion. Our brain stormingsessions on the project left us with headachesand more questions. We were sure of one thing,we would find a way around any obstacle and wewould test this wing during the winter of 19992000.One of the first questions was: if one wing getsthe type of results that we saw with Renee'swork, what would the r~sults be if we put two orthree wings together? We wanted to know thisbecause on the highway we have long sectionsof road that would need to be kept clear. Also,as a continuation of Renee's work, it seemedlogical for the next step.
The Lab that Renee had worked with inAntarctica, had built a proto type wing. Afterseveral calls and e-mails, CRREL (Cold RegionsResearch and Engineering Laboratory, U.S.Army Corps of Engineers) agreed to lone us thewing they had built for our test. We in turn wouldbuild an additional wing and mount them side-byside.
The next question was where do we test? Thisproved harder then we had first thought. Weneeded a place that had a history of drifting. Italso had to be a place where the state eitherowned the right of way or where the landownerwas willing to allow us to perform our test. There
was .also the .concern of safety to .the travelingpublic. Any time you place an object along aroad it has to be engineered to break away ifsomeone hits itor it has to be placed at alocation where there is minimal chance of itgetting hit.
How do we pay for the additional wings? Withthe passage of Initiative-695, any extra moneyfor research and development was gone. Wesolved this problem by enlisting the help of theCascade High School Industrial Arts class. Wesupplied the material, told them what we wantedand they produced the wings. This worked verywell, except that our time frame for completiondid not always coincide with the schedule of thehigh school. The students were veryenthusiastic and the quality of work was verygood.
Cascade High School student welds our wing.
Weather or not
As we all know, the weather is the weather. Justwhen you think you have it all figured out, youfind out you don't. This was the case during ourfirst winter of testing with the two VortexGenerators* in Mansfield Washington. One ofthe biggest problems with using the generatorson a highway is that you are committed to thewind direction depending on Which side of theroad you place them. In our situation, the wingswere placed on the north side of the highwaywhere historically the biggest drifting occurred.As luck would have it we were only able torecord one significant storm that came from thisdirection. Most of the winter storms during the1999-2000 winter came from the oppositedirection.
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'ng that one storm however, it was observedDU~lthe wings did just what we had hoped. Theth~ace area affected by the wings was beingsu ured, while the other road areas on eithersco d 'ft''de did see some n Ing.~ small weather station ~as ~Iaced at the site to
cord wind speed and direction. The datare Heted from this station only confirmed what weCO d' t·visually observed, wrong Irec Ion.
Drifting sand on roadway causes severe traffic hazard.
Sand Sand Sand
In the North Central Region we have a Snow and'Ice Team made up of DOT employees. Therejob is to help other employees in the region dothere job better, safer and more efficiently. Oneof the ways they do this is to investigate and trynew developments in technology, processes andequipment. From the start, the Snow and IceTeam have been and still is, the oil which allowsthis experiment to run.During the winter of 1999-2000, one of themembers of the team asked if the wings wouldwork, or had they ever been tried on sand. Ourfirst reaction was "Oh boy, another question". Itwas however, a good 'question, and it waspassed on to Renee Lang who informed us thatone of her students had been doing some testingwith sand and had some promising results.
From the limited, but encouraging results we hadgotten from our snow site we now turned oureff?rts to the other end of'the region to a placeadjacent the Columbia River where sand fromdunes along the river blows up a steep hill ontothe highway, At times, this sand can build todepth of four to six inches. A car or semitraveling at 55-65 mph and hitting this sand can
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be thrown into an extremely dangerous situation.One of most exciting aspects of this site was thatwe did not have to wait for the sand to fall fromthe sky so it could be blown onto the road. Thewind, because of the topography of the land, wasalready there and we were guaranteed it wouldblow.
A third wing was constructed because of thedistance of roadway we wanted to test. The areaof erosion is in direct relationship to the size ofthe wing. We made our Wings 8 x 8 x 8. Thiswas done in consideration of both cost and size.The bigger they are the harder they are tohandle. Unlike the Mansfield site, we had limitedspace along the roadway to plant the bases, andso were forced to place the wings closer to oneanother then we had hoped. The total length ofroadway for this test was 180 feet. This was withthree wings. At the Mansfield site, this distancewas tested with two wings simply because wewere able to place them further off of theroadway.
In our discussions with Renee, she had told usthat the upward force on the wing created by thewind was insignificant. Because we weredealing with a public highway, and winds at timesin excess of 70 mph, we were not about to takeany chances.All of the bases at both sites were constructed of36" sauna tube 3' deep, filled with 0/.. of a yard ofconcrete. Each base weighed in at around 1500Ibs. Needless to say, they were not going toblow over. The bases were equipped with liftingrods so they can be removed and placed at otherlocations if desired.
Bases were poured on site, but are removable
Immediate results
As luck would have it, the day after we installedthe wings, the wind blew and we were able to getour first real conclusive visual data that the wingsworked. The only real problem we encounteredwas that the guardrail running along the side ofthe road seemed to interfere with the wind flowover the wing. Several options were looked at todeal with this. The option of removing the rail
. was shot down by the legal office. Moving therail out, so it was below the plain of the wing wasshot down because of legal specifications forstate highways. As time went on, the small stripof sand was found not to interfere with traffic.Dealing with this problem is still in the workingstages. From conception of the idea of the wingto this point has been seven months. Everyonewho had been involved with the project was verypleased.
What now?
As we stated in the abstract, this is an on goingproject. We are currently gearing up to place thethree wings from the sand site along theColumbia River, to the Mansfield snow site.There are two main reasons for this. One is thatfor us to conclusively prove that the wings didtheir job on the sand, we must now remove themand see if the original problem returns. If it does,then permanent wings will be installed at thissite.The second reason is that we wO!Jld like toobtain some good snow data. Now that EI Ninoand La Nina have apparently gone away for now,we are causally optimistic that a "normal" winterwill be forth coming and we will be able to obtaingood results. We are also working on placingseveral smoke bombs at the site during a windevent and video taping the actual wind patterns.This may help us in placement of the wings.This will also allow us to obtain data about theexact source location of the sand. Knowing thismay help us in the elimination at the source.
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Strip of sand left by guardrail interfering with wind flow.
If you would like more information on this projectyou may contact us at the phone number or emails listed at the beginning of this paper. If youwould like additional information on the VortexGenerator* you can contact Renee Lang, SigmaTechnologies, (253) 265-3075 or e-mail her atwww.harbornet.com/sigma
* Patent Number # 6053479
