leisure

Putting the Pressure on Roller Coaster Riders By Marc Pagen and Christian Potma, FlowMotion, Delft, the Netherlands Courtesy of Vekoma Rides Manufacturing BV, Vlodrop, the Netherlands

ekoma Rides Manufacturing ing is particularly noticeable on taller BV is a market leader in the roller coasters. To account for high Vglobal amusement industry speeds and wind loading, aerodynamics in the design and manufacture of fam- must play an essential part in the design ily coasters, thrill coasters, and fam- of a modern roller coaster. ily attractions. Boasting a wide The CFD investigation was divid- The Jubilee Odyssey ride at Fantasy Island, Lincolnshire, England is one product range, Vekoma is responsi- ed into two parts, in which a train example of a Suspended Looping Coaster ble for such all-time favorites as the with empty seats or filled with pas- Boomerang, the Invertigo, the sengers was modeled. The geome- Suspended Looping Coaster, and the try of a single two-seat carriage was Junior Coaster. Vekoma’s latest created and copied into a short row developments, the LSM coaster, the to form a representative train. A vol- Flying Dutchman, the Giant umetric mesh of tetrahedral cells was Inverted Boomerang, the Suspended used. Steady-state simulations using Family Coaster, and the Tilt Coaster, the k-ε turbulence model were per- are driving the roller coaster indus- formed for several wind speeds and try of the future by setting new stan- directions. Based on the CFD results, dards for quality and innovation. the aerodynamic coefficients were cal- Vekoma has sought the assistance culated. of FlowMotion for the optimization The FLUENT simulations indicated of their High Speed Suspended that for the Suspended Looping Looping Coaster Train. FlowMotion Coaster, the size and shape of the is a Dutch engineering consultancy wake behind the leading carriage is firm specializing in fluid dynamics. critical for the overall aerodynamic Having gained experience with sev- drag of the train. While extensive In a twisting section of the track, the eral CFD codes, FlowMotion has select- streamlining of the first carriage may carriages move outside the wake of ed FLUENT for its ease-of-use in various reduce its wake, it can also lead to the preceeding carriage industrial applications. more exposure of the second car- A roller coaster is essentially a grav- riage to the undisturbed wind, ity-powered train. When the train is resulting in a higher overall drag. Also, pulled up the first hill, gravitational in high speed twisting parts of the potential energy is transferred to the track, the drag is increased consid- train. Once the train begins to erably when the individual two-seat descend, the gravitational potential carriages fan out and more frontal energy is transferred to kinetic ener- area of the train is exposed to the gy, the energy of motion. During the wind. Based on the CFD results, a ride, there is a continuous conversion redesign of the seat shape was done of energy back and forth between the that balanced the operating require- two forms, but gradually energy is lost ments and resulted in a significant to friction and air resistance, and the performance improvement. At latter can affect the speed and Vekoma, CFD simulations using length of the ride. As modern roller FLUENT have generated a new under- coasters become faster and the rides standing of the behavior of their roller longer, the structures increase in size. coasters and have given the design- Total pressure on the occupants Because wind conditions are often more ers new inspiration to develop even and support structure of the ■ leading three carriages is shown severe at greater heights, wind load- more exciting rides in the future. in a twisting section of the track

Fluent NEWS fall 2003 21