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A novel method was developed to predict the free-stream velocity experienced by a traveling vehicle based on track-side anemometric measurements. The end objective of this research was to enhance the reliability of the prediction of free-stream conditions in order to improve the accuracy of aerodynamic drag coefficient (CD) assessments from track tests of surface vehicles. Although the technique was applied to heavy-duty vehicles in the present work, it is equally applicable to any vehicle type. The proposed method is based on Taylor’s hypothesis, a principle applied in fluid mechanics to convert temporal signals into the spatial domain. It considers that the turbulent wind velocity fluctuations measured at one point are due to the "passage of an unchanging pattern of turbulent motion over the point". The method is applied to predict the wind velocity that the vehicle will experience as it encounters a wind pattern detected earlier by an anemometer located upwind.

The concentration of carbonaceous particulate matter in the exhaust of diesel engines depends on the rates of formation and oxidation of soot in the combustion chamber. Soot forms early in the combustion process when local fuel-rich areas exist, whereas soot oxidation occurs later when more air is entrained into the fuel spray. Based on this understanding, a phenomenological combustion model is established. In the model, the cylinder volume is divided into four zones: a rich fuel spray core, a premixed-burning/burned gas zone, a mixing controlled burning zone and a lean air zone. Soot formation takes place in the mixing controlled burning zone where the local C/O ratio is above the critical value. Soot oxidation occurs in the premixed-burning/burned gas zone as air is entrained. By using a quasi-global chemical reaction scheme, the oxidation of soot particles by different species can be investigated.

Turbulence is known to influence the aerodynamic and aeroacoustic performance of ground vehicles. What is not thoroughly understood are the characteristics of turbulence that influence this performance and how they can be applied in a consistent manner for aerodynamic design and evaluation purposes. Through collaboration between Transport Canada and the National Research Council Canada (NRC), a project was undertaken to develop a system for generating road-representative turbulence in the NRC 9 m Wind Tunnel, named the Road Turbulence System (RTS). This endeavour was undertaken in support of a larger project to evaluate new and emerging drag reduction technologies for heavy-duty vehicles. A multi-stage design process was used to develop the RTS for use with a 30% scale model of a heavy-duty vehicle in the NRC 9m Wind Tunnel.

The Flight Research Laboratory (FRL), National Research Council (NRC) of Canada is currently developing an in-flight aircraft aerodynamic model identification technique that determines the small perturbation model at a given test condition. Initial demonstrations have been carried out using the NRC Falcon 20 research aircraft. An efficient system architecture, in terms of both software algorithms and hardware processing, has been designed to meet the stringent near real-time requirements of an in-flight system. As well, novel hardware and software techniques are being applied to the calibration and measurement of the fundamental in-flight parameters, such as air data. The small perturbation models are then combined to develop a global model of the aircraft that is validated by comparing the model response to flight data. The maneuvers were performed according to the FAA Acceptance Test Guide (ATG).

This paper describes an investigation of the performance potential of conventional flat-panel boat-tail concepts applied to tractor-trailer combinations. The study makes use of data from two wind-tunnel investigations, using model scales of 10% and 30%. Variations in boat-tail geometry were evaluated including the influence of length, side-panel angle and shape, top-panel angle and vertical position, and the presence of a lower panel. In addition, the beneficial interaction of the aerodynamic influence of boat-tails and side-skirts that provides a larger drag reduction than the sum of the individual-component drag reductions, identified in recent years through wind-tunnel tests in different facilities, has been further confirmed. This confirmation was accomplished using combinations of various boat-tails and side-skirts, with additional variations in the configuration of the tractor-trailer configuration.

One of the main applications for aluminum extrusions in the automotive sector is crash structures including crash rails, crash cans, bumpers and structural body components. The objective is usually to optimize the energy absorption capability for a given structure weight. The ability to extrude thin wall multi-void extrusions contributes to this goal. However, the alloy used also plays a significant role in terms of the ability to produce the required geometry, strength - which to a large extent controls the energy absorption capability and the “ductility” or fracture behavior which controls the strain that can be applied locally during crush deformation before cracking. This paper describes results of a test program to examine the crush behavior of a range of alloys typically supplied for automotive applications as a function of processing parameters including artificial ageing and quench rate.

This article presents an autonomous steering control scheme for articulated heavy vehicles (AHVs). Despite economic and environmental benefits in freight transportation, lateral stability is always a concern for AHVs in high-speed highway operations due to their multi-unit vehicle structures, and high centers of gravity (CGs). In addition, North American harsh winter weather makes the lateral stability even more challenging. AHVs often experience amplified lateral motions of trailing vehicle units in high-speed evasive maneuvers. AHVs represent a 7.5 times higher risk than passenger cars in highway operation. Human driver errors cause about 94% of traffic collisions. However, little attention has been paid to autonomous steering control of AHVs.

In recent years, light weight components have been an area of significant importance in automotive design. This has led to the replacement of steel and cast iron with aluminum alloys for many automotive components. For instance, Al-Si alloys have successfully replaced nodular and gray cast iron in the production of large automotive components such as engine blocks. However, excessive residual strain along the cylinder bores of these engine blocks may result in cylinder distortion during engine operation. Therefore, in this study, neutron diffraction was used to evaluate residual strain along the aluminum cylinder bridge and the gray cast iron liners of distorted and undistorted engine blocks. The strains were measured in the hoop, radial, and axial orientations. The results suggest that the residual strain along the aluminum cylinder bridge of the distorted engine block was tensile for all three measured components.

Continuous efforts to develop a lightweight alloy suitable for the most demanding applications in automotive industry resulted in a number of advanced aluminum (Al) and magnesium alloys and manufacturing routes. One example of this is the application of 319 Al alloy for production of 3.6L V6 gasoline engine blocks. Aluminum is sand cast around Fe-liner cylinder inserts, prior to undergoing the T7 heat treatment process. One of the critical factors determining the quality of the final product is the type, level, and profile of residual stresses along the Fe liners (or extent of liner distortion) that are always present in a cast component. In this study, neutron diffraction was used to characterize residual stresses along the Al and the Fe liners in the web region of the cast engine block. The strains were measured both in Al and Fe in hoop, radial, and axial orientations. The stresses were subsequently determined using generalized Hooke's law.

A joint program between Bell Helicopter Textron Canada and the Flight Research Laboratory of Canada's National Research Council was initiated to address the aerodynamic modelling challenges of the Bell M427 helicopter. The primary objective was to use the NRC parameter estimation technique, based on modified maximum likelihood estimation (MMLE), on a limited set of flight test data to efficiently develop an accurate forward-flight mathematical model of the Bell M427. The effect of main rotor design changes on the aircraft stability characteristics was also investigated, using parameter estimation. This program has demonstrated the feasibility of creating a forward-flight rotorcraft aerodynamic mathematical model based on time-domain parameter estimation, and the ability of a 6 degree-of-freedom MMLE model to accurately document the impact of minor rotor modifications on aircraft stability.

This paper examines issues related to planning, programming and execution of machining operations by a robot in the context of machining large parts with complex geometries by a gantry-mounted robotic system. Parts were created from surface data in a CAD/CAM environment. The same environment was used to generate tool paths using a conventional machine tool approach. These paths were converted to robot trajectories and validated using mathematical kinematic models of the robotic system. Validation was performed according to various criteria related to process performance. Associated robot programs were then automatically generated. The manufacturing cell was progressively integrated according to requirements resulting from iterative process characterization. A metrology-based calibration procedure was designed that considerably improved the system's positioning precision.

The use of carbon fiber reinforced thermoset composites has doubled in the last decade raising questions about the waste generated from manufacturing and at end-of-life, especially in the aircraft industry. In this study, 2.5 cm long carbon fibers were recovered from thermoset composite waste using a commercial scale pyrolysis process. Scanning electron microscopy, density measurements, single filament tensile testing as well as micro-droplet testing were performed to characterize the morphology, mechanical properties, and surface adhesion of the fibers. The recycled fibers appeared to be mostly undamaged and clean, exhibiting comparable mechanical properties to virgin carbon fibers. A carding process followed by an ultrasound treatment produced randomly aligned recycled fiber mats. These mats were used to fabricate composite plates, with fiber volume fractions up to 40 %, by infusion / compression molding.

Future compliance to FAA 14 CFR Part 25 and EASA CS-25 Appendix O conditions has required icing wind tunnels to expand their cloud simulation envelope, and demonstrate accurate calibration of liquid water content and droplet particle size distributions under these conditions. This has led to a renewed community interest in the accuracy of these calibrations, and the potential inter-facility bias due to the choice of instrumentation and processing methods. This article provides a comparison of the response of various hot-wire liquid water content instruments under Appendix C and supercooled large droplet conditions, after an independent similar analysis at other wind tunnel facilities. The instruments are being used, or are under consideration for use, by facilities collaborating in the ICE GENESIS program.

A comparison of scanning mobility particle sizer (SMPS) and laser-induced incandescence (LII) measurements of diesel particulate matter (PM) was performed. The results reveal the significance of the aggregate nature of diesel PM on interpretation of size and volume fraction measurements obtained with an SMPS, and the accuracy of primary particle size measurements by LII. Volume fraction calculations based on the mobility diameter measured by the SMPS substantially over-predict the space-filling volume fraction of the PM. Correction algorithms for the SMPS measurements, to account for the fractal nature of the aggregate morphology, result in a substantial reduction in the reported volume. The behavior of the particulate volume fraction, mean and standard deviation of the mobility diameter, and primary particle size are studied as a function of the EGR for a range of steady-state engine speeds and loads for a turbocharged direct-injection diesel engine.

The 9-meter wind tunnel of the National Research Council (NRC) of Canada is commonly employed in testing of class 8 tractors at full- and model-scales. In support of this work a series of tests of an identical model at full- and half-scale were performed to investigate some of the effects resulting from simulation compromises. Minimum Reynolds Number considerations drive the crucial decisions of what scale and speed to employ for testing. The full- and half-scale campaigns included Reynolds Number sweeps allowing conclusions to be reached on the minimum Reynolds number required for testing of fully-detailed commercial truck models. Furthermore the Reynolds sweeps were repeated at a variety of yaw angles to examine whether the minimum Reynolds Number was a function of yaw angle and the resulting flow regime changes. The test section of the NRC 9-meter wind tunnel is not sufficiently long to accommodate a full-scale tractor and a typical trailer length of 48′ or more.

Controlling the forming of large thermoplastic parts from a simulation requires very precise predictions of the pressure and volume profile evolution. Present pressure profile based simulations adequately predict the thickness distribution of a part, but the forming pressure and volume profile development lack the precision required for process control. However new simulations based on the amount of power required to form the material can accurately predict these pressure and volume profiles. In addition online monitoring of the forming power on existing machines can be easily implemented by installing a flow rate and pressure meter at the gas entrance, and if necessary, exits of the part. An important additional benefit is that a machine thus equipped can function as an online rheometer that can characterize the viscosity of the material at the operating point by tuning the simulation to the online measurements.

Under contract to Transport Canada (TC) and with joint funding support from the Federal Aviation Administration (FAA), a vertical stabilizer common research model (VS-CRM) has been designed and built by the National Research Council of Canada (NRC). This model is a realistic, scaled representation of modern vertical stabilizer designs without being specific to a particular aircraft. The model was installed and tested in the NRC 3 m × 6 m Icing Wind Tunnel in late 2021/early 2022. Testing was led by APS Aviation Inc., with support from NRC and NASA, in order to observe the anti-icing fluids flow-off behavior with and without freezing or frozen precipitation during simulated take-off velocity profiles. The model dry-air aerodynamic properties were characterized using flow visualization tufts and boundary layer rakes. Using this data, a target baseline configuration was selected with a yaw angle equal to 0° and rudder deflection angle equal to -10°.

In 2017 the National Research Council of Canada developed an evaporation model for controlling engine icing tunnels in real time. The model included simplifications to allow it to update the control system once per second, including the assumption of sea level pressure in some calculations. Recently the engine icing system was required in an altitude facility requiring operation down to static temperatures of -40°C, and up to an altitude of 9.1 km (30 kft) or 30 kPa. To accommodate the larger temperature and pressure range the model was modified by removing the assumption of sea level operation and expanding the temperature range. In addition, due to the higher concentration of water vapor that can be held by the atmosphere at lower pressures, the significance of the effect of humidity on the air properties and the effect on the model was investigated.

The demand for light weight vehicles continues to stimulate extensive research into the development of light weight casting alloys and optimization of their manufacturing processes. Of primary relevance are Aluminum (Al) and Magnesium (Mg) based alloys, which have successfully replaced selected iron based castings in automobiles. However, optimization of as-cast microstructure, processing and performance remains a challenge for some Al-based alloys. In this context, placement of chills in castings has been frequently used to locally manipulate the solidification conditions and microstructure of a casting. In this work, the effect of using an active copper chill on the residual strain profile of a sand-cast B319 aluminum alloy was investigated. Wedge-shaped castings were produced with three different cooling conditions: copper plate chill, copper pipe with cooling water and no chill (baseline).

Computational fluid dynamics (CFD) model has been widely applied in internal combustion (IC) engine research. The integration of chemical kinetic model with CFD provides an opportunity for researchers to investigate the detailed chemical reactions for better understanding the combustion process of IC engines. However, the simulation using CFD has generally focused on the examination of primary parameters, such as temperature and species distributions. The detailed investigation on chemical reactions is limited. This paper presents the development of a post-processing tool capable of calculating the rate of production (ROP) of interested species with the known temperature, pressure, and concentration of each species in each cell simulated using CONVERGE-SAGE CFD model.