Aerodynamic optimization of a high-speed train

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Source: Optimal Solutions Software

The high-speed train market in recently industrialized countries is one of the most hotly contested engineered-product markets in the world, with even the smallest advantage important in gaining a competitive edge. In particular, fuel consumption is a critical factor in design, sales and maintenance of these vehicles. In this project, a manufacturer of high-speed rail vehicles needed to maximize efficiency, reduce emissions and decrease design time.

Seeking a more efficient engineering approach that would let it maximize the number of designs that could be tested within the project schedule, the manufacturer selected Sculptor from Optimal Solutions Software. By specifying key design parameters, the software allows hundreds of designs to be generated in a matter of minutes—a radical improvement over the company’s previous process, in which this phase of the project took months.

Sculptor, coupled with ESTECO’s modeFRONTIER for multi-objective optimization and CD-adapco’s STAR-CCM+ for CFD analysis, allowed the customer to find an aerodynamic design that decreased drag by more than 5%, increasing aerodynamic efficiency and therefore fuel economy. All design changes were completed in less than one hour, whereas using either conventional CFD approaches or wind-tunnel testing would have required weeks or months. Sculptor eliminated time-consuming manual operations on both the vehicle CAD model and the CFD grid, since its morphing takes place on the CFD model directly.

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Source: Optimal Solutions Software

Using Arbitrary Shape Deformation (ASD) volumes, different configurations were instantly tested without the need to manually recreate the mesh. In all, 100 different geometries were tested, and one was found that reduced drag by 5.88%.

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Source: Optimal Solutions Software

Five control groups were defined with individual deformation vectors based on manufacturing constraints and realistic aerodynamic estimations. These groups were used as design variables in the optimization setup.

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Source: Optimal Solutions Software

Sculptor’s morphing technology combined with the five control groups was applied over the CFD model of the train. Using the optimizer to determine which configurations should be tested, Sculptor took 15 minutes to generate 36 designs, which were then automatically sent to the CFD code and analyzed.

Sculptor coupled with STAR-CCM+ allowed the optimal aerodynamic design to be found in a few days, whereas using CFD only would have taken several weeks. With 80 designs that needed to be evaluated, total costs for this activity were reduced to just 8% of what they would have been with the company’s traditional engineering methods, based on estimated labor cost of $90 per hour, CFD code cost of $10.75 per hour and Sculptor cost of $10.75 per hour.

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Source: Optimal Solutions Software