Airflow is simulated over and past the wing of a high performance aircraft that is using vectored thrust while descending to a few feet above the ground (in ground effect).
Improved design and simulation of advanced aerospace vehicles is a primary goal of the NASA HPCC Program. Massively parallel processing and related high performance computing technologies are enabling new simulation and optimization methodologies for flight vehicle design. These methodologies combine multiple physical disciplines and integrate vehicle components such as the airframe, propulsion systems, and controls. Improved aircraft design resulting from high performance computing promises to give the U.S. aerospace industry a critical competitive edge. Early and continuous coordination between NASA research centers, other Federal agencies, academia and industry is crucial to the success of this endeavor.
Scientists at NASA's Ames Research center have developed computer simulations of air flow past a delta wing at takeoff and landing that will help design more efficient and cost-effective aircraft. By porting a single discipline computational fluid dynamics code to a number of scalable parallel computers, the scientists simulated applications involving moderately complex geometries. For example, a simple powered lift vehicle that includes a wing and two lifting jetson is shown on the previous page. Navier Stokes computations were performed to simulate flow past a delta wing with thrust reverser jets in a ground effect environment (takeoff and landing). These preliminary simulations will provide insight into the computational interaction of thrust elements, and upwash and reingestion of hot air and gases, leading to significant improvements in aerodynamic performance.
Airspeed contours around a three-dimensional aircraft traveling at Mach 0.77 are revealed by using an advanced simulation method (lower figure). Blue areas represent slower moving air, yellow and red the fastest moving air. Flow calculations for this complex geometry were based on the unstructured mesh shown in the upper figure.
Improved design processes for advanced aircraft and spacecraft through the use of advanced computational fluid dynamics and structural analyses is also the subject of research by scientists at Langley Research center. Scientists are focusing on the design and modeling of a High Speed Civil Transport (HSCT). One of the greatest challenges in modeling the fluid dynamics of these vehicles is developing mathematical equations that accurately simulate turbulent airflow. Turbulent flow simulations currently used lose accuracy at high speeds. Development of an optimal airframe design for a HSCT involves thousands of design iterations, each requiring a large amount of computing time to recalculate how changes in one part of the design affect the rest of the structure. Langley scientists have developed a method to streamline this part of the overall process and reduce the amount of computing time needed for each iteration.
Airflow through several components of a jet engine is simulated on a cluster of IBM RISC 6000 workstations.
Researchers at NASA Lewis Research center are developing a prototype Numerical Propulsion System Simulator (NPSS) that will allow dynamic numerical and visual simulation of engine components. The prototype is intended to simplify the process of dynamically connecting engine component software across various machine architectures. This will allow industry to design, engineer, and fabricate tomorrow's propulsion systems. This multidisciplinary research, coupled with the improved performance offered by massively parallel computers, will greatly enhance the ability of aircraft manufacturers to analyze different design options rapidly and then efficiently produce vehicle propulsion systems with optimal performance and reduced design cycle costs.