Existing methods of numerically solving the euler equations existing methods of numerically solving the euler equations use a linearization in either real or artificial time so that at each step of the solution path well known techniquescan be used. this linearization is performed about the solution… More

Most of the numerical codes for solving the compressible navier-stokes equations or the euler equations in use today are based on finite difference schemes. most of these schemes are linear. nonlinear schemes, however, have more desirable properties such as monotone preserving, increased accuracy,… More

The objective of the proposed investigation is to develop a method to predict the trajectory of a submarine launched ballistic missile (slbm) between launch and broach. the method will consider such effects as the unsteady motion of the submarine during launch, submarine wake-induced effects, and… More

A procedure is proposed for the design of missile control surfaces using aeroelastic tailoring to enhance their performance. the principal goal of the procedure is to minimize the variation of the chordwise position of the aerodynamic center of pressure as the surface deforms under load. other… More

The proposed work concerns a novel approach to the study of aerodynamics during transient maneuvers. previous work has shown that augmented aerodynamic characteristics, such as very high lift coefficient, may be obtained due to the transient nature of some maneuvers. the fluid mechanics that affect… More

A program of work leading to the development of a prediction capability applicable to advanced air force fighter configurations in unsteady maneuvers involving nonlinear, time-dependent aerodynamic characteristics is proposed. existing advanced computational techniques to predict the forces and… More

Numerical predictions of ground effects flow suffer loss of accuracy because of inadequate turbulence models and because of the inability to treat complex aircraft geometry in an economical manner. one objective of phase i is to demonstrate that data from numerical simulations of turbulence can be… More

It is known that the nonlinear navier-stokes equations will model most fluid flow of aeronautical interest. the existence and uniqueness of the solution to the navier-stokes equations have not been proven although it is shown that in certain instances more than one solution can be found. in a wind… More

The modeling and calculation of supersonic turbulent reacting flows are considered. it is suggested that accurate prediction of such flow fields depends on a thermochemical model that, while being simple, can account for dominant time scales involved in the reaction and a turbulence model capable of… More

A program of work is proposed leading to the prediction and understanding of the aerodynamics acting on a missile or an airplane flying at low altitude over the sea surface. it appears that close to the sea surface, the unsteady nature of the ambient air is of sufficiently high frequency to cause… More

A program of work leading to an analytical capability to predict the postlaunch behavior of torpedo guidance wires in the vicinity of maneuvering submarines is described. an existing method to predict the complex unsteady flow field near the launch vehicle will be combined with a method to predict… More

Because of recently defined tactical threats it is desirable to improve the maneuverability and take-off/landing aspects of aircraft performance. it has been determined that such improvements can be accomplished by the use of thrust reversers or vectored jets. in order to design aircraft… More

One of the most important issues in developing computationalfluid dynamics for hypersonic flow is turbulence modeling. one of the unique aspects of hypersonic flow is the effect of the shock waves on turbulence, an effect that is considerable. previous work has found that current turbulence models… More

Atmospheric science involves studies of very complex physical processes. often, simplified versions of these processes are simulated in a laboratory or on a computer. computational fluid dynamics (cfd) methods provide a good way to perform these simulations of atmospheric phenomena, since they allow… More

Ice accretion on components of both fixed wing aircraft and rotorcraft can cause aerodynamic penalties such as increaseddrag, decreased lift, reduced stall angle, increased stall speed and increased engine horsepower requirements. there is currently a strong need for developing accurate and… More

A program of work leading to an analytical computational fluid dynamics (cfd) capability to predict the detailed fluid mechanics of an ejection seat during high speed ejection is described. the method will consider transonic flows at high dynamic pressures including effects of shock waves and… More

Chaos theory has recently suggested two innovative strategies for active control of general, nonlinear systems. both are potentially applicable to the problem of controlling shear flows, whether it be to enhance or suppress the effects of turbulence. each makes essential use of the nonlinear… More

High-speed endo-atmospheric interceptors need cooling to protect the body and homing sensors from hot external flow. The windows for infrared seekers are cooled with some form of wall jet(s), but turbulence generated in the mixing layer between the cooling jet(s) and the external flow distorts the… More

The phase i investigation will demonstrate the feasibility of an analytical approach to predict the high angle-of-attack aerodynamic characteristics of agile fighter aircraft and tactical missiles in dynamic multi-axis maneuvers. an innovative combination of theory and experiment will produce… More

Within DoD there is a current need for the design or redesign of aircraft-borne weapon airframes to meet conformal/internal carriage requirements. A major constraint imposed by confromal/internal carriage is a limitation on the maximum stowable fin span of a weapon. Current aircraft such as the… More

Maneuvering aircraft at high angles of attack experience severeunsteady loading. This loading, when unanticipated at the designstage, can cause fatigue problems and, possibly, structuralfailure. Such instances have occurred in the past, for example

Drag reduction via active control of wing boundary layers will result in substantial performance and range improvements for both military and commercial aircraft. The increased efficiency will reduce costs in both sectors and increase profitability of commercial operations. Key to the success of an… More

Drag due to turbulent skin friction substantially penalizes the performance and economics of oil and gas pipelines. using two new control ideas originating from research in nonlinear dynamical systems, researchers have recently used numerical simulations to demonstrate the possibility of 50-60… More

This proposal is concerned with the use of massively parallel computers for performing mesoscale numerical weather predictions (NWP). For the Phase I effort, a simple, but realistic model weather problem will be implemented on a parallel computer. The goal of the proposed research is to demonstrate… More

The proposed research will determne the feasibility of extending the steady and unsteady aerodynamic modeling capabilities of ASTROs using modern nonlinear Computational Fluid Dynamics. The object of Phase I is to explore the technical means by which CFD codes can be efficiently integrated into the… More

Nielsen Engineering & Research (NEAR) is proposing the development of a practical, variable geometry fluid mechanical control surface which offers reduced weight, complexity, power consumption, and cost as compared to other potential solutions. The complete system incorporates an array of surface… More

The use of CFD in the design and analysis of flight vehicles requires specialized knowledge about factors such as algorithm options, gridding methods, physical models, and runtime performance. This knowledge is needed to properly set up a calculation and to monitor the solution during… More

The goal of the proposed research is to evaluate the use of nonlinear indicia function to efficiently model unsteady aerodynamic responses. Despite the need for enhanced aerodynamic prediction capabilities in flight simulations of maneuvering aircraft, using state-of-the-art solutions of the… More

The overall objective of the proposed SBIR project is to develop a highly accurate, dynamically adaptive grid, Navier-Stokes prediction methodology which will be applicable to the problem of dynamic stall. four tasks are proposed: (1) evaluation of trade-offs and identification of potential… More

The proposed work will decrease the computer CPU time required for computational fluid dynamics (CFD) caluations by two orders of magnitude relative to CFD methods currently used for design. This will be done through the use of high-accuracy spatial discretization schemes and high-over outer… More

The proposed work will use computational fluid dynamics (CFD) methods with high-accuracy spatial discretization and improved modeling to provide accurate predictions of weapon bay flows. The spatial discretization scheme to be used has accuracy similar to that of spectral methods, and it can … More

The proposed work will test the feasibility of using a relatively new three-equation turbulence model to achieve accurate predictions of nonequilibrium turbulence in flows related to high-lift systems for military aircraft. It has been demonstrated analytically and in calculations of … More

Nielsen Engineering & Research (NEAR) proposes to employ its updated flexible fin and fin planform optimization technologies to control/minimize missile fin hinge moments while maintaining normal force required for high g maneuvering. In the Phase I effort, sensitivity studies will be performed… More

Nielsen Engineering & Research (NEAR) proposes to develop a new missile control fin design method to maximize fin normal force, minimize actuator requirements, and control fin wake. Current design methods do not adequately model fin-body gap effects. CFD technology will be employed to provide… More

The goal of the work is to develop a physics-based method for predicting clear air turbulence (CAT). Two levels of prediction will be employed: direct simulation of the intermediate scales of motion based on numerical integration of the Navier-Stokes equations (referred to by the generic term… More

Nielsen Engineering & Research (NEAR) is proposing the development of a practical, variable geometry fluid mechanical control surface which offers reduced weight, complexity, power consumption, and cost as compared to other potential solutions. The complete system incorporates an array of surface… More

Nielsen Engineering & Research (NEAR) is proposing to investigate the feasibility of two innovative solid-state concepts for MEMS-based turbulent wall shear-stress transducers. The first design, which relies on the variation in acoustic convection velocity through the boundary layer, employs… More

Effective suppression of jet engine noise by inlet and exhaust duct liners continues to be an important part of producing environmentally acceptable aircraft. Because methods for transfer of frequency-domain impedance data to time-domain boundary conditions are still under development, Computational… More

In both ground and flight tests, important information about aerospace vehicle performance can be derived from knowledge of the boundary layer profiles above the vehicle's surface. However, measuring these profiles is often difficult, since an instrument or instrument rake must be extended/swept… More

Although anticipated developments in directed energy weaponry require the characterization of electromagnetic hardness with respect to short duration electromagnetic pulse energies, continuous wave (CW) radiation, rather than pulse bombardment, iscurrently used to nondestructively test aircraft… More

Although anticipated developments in directed energy weaponry require the characterization of electromagnetic hardness with respect to short duration electromagnetic pulse energies, continuous wave (CW) radiation, rather than pulse bombardment, iscurrently used to nondestructively test aircraft… More

An automated documentation and reporting system for computational data is proposed. This system will automatically collect and store calculation data, such as input values, grid parameters, and solution quality measures, and will store this information as text, numerical data, and graphics in a… More

An automated documentation and reporting system for computational data is proposed. This system will automatically collect and store calculation data, such as input values, grid parameters, and solution quality measures, and will store this information as text, numerical data, and graphics in a… More

The objective of this proposal is to apply a new high-order accurate in space computational approach in the OVERFLOW code in order to resolve the essential features of helicopter flowfields more efficiently. The potential of the proposed method to improve resolution of tip vortices and rotor wakes… More

The objective of this proposal is to apply a new high-order accurate in space computational approach in the OVERFLOW code in order to resolve the essential features of helicopter flowfields more efficiently. The potential of the proposed method to improve resolution of tip vortices and rotor wakes… More

Effective suppression of jet engine noise by inlet and exhaust duct liners continues to be an important part of producing environmentally acceptable aircraft. Because methods for transfer of frequency-domain impedance data to time-domain boundary conditions are still under development, Computational… More

Effective suppression of jet engine noise by inlet and exhaust duct liners continues to be an important part of producing environmentally acceptable aircraft. Because methods for transfer of frequency-domain impedance data to time-domain boundary conditions are still under development, Computational… More

"To meet current and future operational and tactical refueling requirements, an innovative, single-solution hose/drogue refueling system is needed which spans a speed range from 95 to 280 knots - a dynamic pressure range in excess of 8:1. NEAR hasdeveloped a range of potential solutions which… More

"Nielsen Engineering and Research (NEAR) is proposing to develop, fabricate, and demonstrate a prototype ultrasonic vortex detection system. The proposed instrument uses the time-of-flight of an acoustic signal as it traverses around the inside of thebellmouth to compute the strength of any… More

"The work will identify the most promising long-term approach to upgrading the CFDmodeling of store separation for Air Force flight vehicles. Two likely optionsare identified in the Phase I proposal, and the relative merits of these methodswill be studied in depth in the Phase I work. Both… More

"An engineering analysis tool for fast and accurate calculations of the aerodynamicand aerothermodynamic characteristics of multistage rocket sled vehicles at subsonicthrough hypersonic Mach numbers is proposed. The Phase I feasibility study willevaluate the use of component buildup methods which… More

New aircraft types entering service with the Air Force, Navy, and Marine Corps (e.g., tilt rotor and unmanned combat air vehicles) have created a demand for new and advanced aerial refueling systems. With the introduction of the V-22 aircraft, there is arequirement for a single hose-drogue… More

Aeroelastic studies, such as the prediction of flutter boundaries and limit cycle oscillations, play a critical role in aircraft safety and design. To perform these analyses with the required accuracy, nonlinear aerodynamic, and possibly nonlinear structural, effects must be included. Furthermore,… More

Many direct-connect turbine engine test facilities use a bellmouth for transitioning between the plenum and the engine air supply duct. Under certain test conditions, vorticity can form at the plenum/bellmouth interface which causes errors in air flowmeasurements and affects engine performance. To… More

An unstructured-grid capability will be added to the CFD code Beggar using overset methods. Beggar's polygonal mapping tree technology will be extended to unstructured grids, to quickly establish connectivity between overset grids. An existingunstructured-grid CFD solver will be modified to work… More

An engineering analysis tool (RSX) for fast and accurate calculations of the aerodynamic characteristics of multistage rocket sled vehicles at supersonic through hypersonic Mach numbers has been demonstrated in the Phase I feasibility study. Initialresults show critical shock interactions with… More

Nielsen Engineering & Research (NEAR) is proposing to develop a robust, nonintrusive aerodynamic shear stress sensor for use in aircraft flight testing. This sensor is based on technology developed by NEAR under a previous SBIR contract. In the proposed Phase I contract, NEAR will take this… More

Computational fluid dynamics (CFD) is the primary tool of aerodynamic design, and the ability to reduce and quantifyuncertainties in CFD results is essential. Efforts throughout theCFD community are aimed at improving the accuracy of CFD methods. The proposed work will develop computational… More

Computational fluid dynamics (CFD) is the primary tool of aerodynamic design, and the ability to reduce and quantify uncertainties in CFD results is essential. Efforts throughout the CFD community are aimed at improving the accuracy of CFD methods. The proposed work will develop computational… More

Through numerical simulations and wind tunnel testing, Nielsen Engineering & Research (NEAR) has demonstrated that their acoustic sensing technology can be used to quantify the magnitude and direction of the local shear stress vector. Because the instrument can 1) measure shear stress values up to… More

Testing and Evaluation (T&E) is crucial in determining the operational limits of air vehicles aboard various classes of ships. The cost of conventional testing of air vehicles and ships continues to escalate in a world of tightening project budgets; therefore, the required flight testing time must… More

Reducing uncertainty in the prediction of limit cycle oscillations (LCO) and other nonlinear aeroservoelastic phenomena is critical to flight safety. To do so requires nonlinear methods. First-principles based methods (CFD/CSD) have made considerable progress but still cannot predict LCO from the… More

This work seeks to develop the technology needed to launch oversized payloads using nonconventional asymmetric payload fairings. These fairing present significant challenges with respect to stability and control, structural integrity, and payload environment. The Phase I effort will involve… More

An explosion of geographic data sets and related processing has occurred in recent years. Spatial data mining techniques are of interest to handle these large volumes of data and to identify relationships between features in a data set. Data mining holds the promise of being able to discover and… More

Geographic information processing and spatial data analysis activities have increased dramatically in recent years, and data mining techniques have the potential to automate some of these processing tasks. Spatial data mining can be used to identify relationships between features in a data set and… More

Testing and Evaluation (T&E) is crucial in determining the operational limits of air vehicles aboard various classes of ships. The cost of conventional testing of air vehicles and ships continues to escalate in a world of tightening project budgets; therefore, the required flight testing time must… More

The work will develop a large asymmetric payload fairing for use in launching over-sized payloads. Issues to be addressed include the reduction of aerodynamic forces to maintain stability and control, strength and weight of the fairing, control of aerodynamic buffet, and attenuation of dynamic… More

Nielsen Engineering & Research (NEAR) and The University of Kansas Center for Research (KUCR) propose the development of an innovative integral control surface and actuator system which can be used to achieve pitch, roll, and yaw control of a miniature hypersonic vehicle. The proposed system uses… More

This effort proposes to develop methods that can be used to quantify and reduce the errors in CFD. Predictions of error and uncertainty in CFD solutions will be obtained from solutions of partial differential equations (PDEs) for these quantities. This approach has a mathematical basis that… More

Nielsen Engineering & Research (NEAR) is proposing to develop an innovative controllable drogue system based on their CDC7 technology. During the Phase I effort, a second generation CDC7 design, which meets the Navy's specific needs, will be developed through numerical analysis and full-scale wind… More

Nielsen Engineering & Research (NEAR) is proposing to develop a new flex-hose system that will allow USN submarines to deploy the Mk 48 torpedo in shallow water or in close proximity to the sea floor. A number of concepts are proposed that can potentially keep the flex-hose an acceptable distance… More

Future adaptive, smart air vehicles will continually tune themselves using sophisticated on-board health management and on-the-fly optimization of performance parameters. To support these dynamic, complex/nonlinear, and multidisciplinary optimization tasks requires novel methodologies. These new… More

Nielsen Engineering & Research (NEAR) is proposing to develop a new and innovative tow system for the AN/ASQ-233 magnetometer. The system will be small and light enough to allow its use with manned and unmanned fixed- and rotary-wing aircraft. The tow body will be stabilized to 1/2 degree in all… More

In the proposed Phase II effort, Nielsen Engineering & Research (NEAR) will continue developing the two advanced flex-hose systems that were selected from the seven investigated during the Phase I feasibility study. The resulting system will allow the successful deployment of Mk 48 torpedoes from… More

This proposal seeks to pioneer innovative methods for managing data on various levels of fidelity through extensions of previous methods, computational results, and rigorous mathematical results. Specifically, Multifidelity Sequential Kriging Optimization (MFSKO) will be extended to address… More