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Seeks to study the dependence of the shear strength of a fluid on the fluid pressure and the bulk fluid temperature, respectively, theoretically for given bulk fluid temperatures and fluid pressures in the whole ranges of fluid pressure and bulk fluid temperature.

The analyses are, respectively, carried out with emphasis on the dependence of the shear strength of a fluid in liquid state, i.e. at low pressures on the fluid pressure and the bulk fluid temperature for given bulk fluid temperatures and fluid pressures based on the theory of the compression of the fluid by the pressurization of the fluid.

The fluid shear strength versus fluid pressure curve in the whole range of fluid pressure and the fluid shear strength versus bulk fluid temperature curve in the whole range of bulk fluid temperature, respectively, for a given bulk fluid temperature and a given fluid pressure are obtained. It is shown by this fluid shear strength versus fluid pressure curve that, for a given bulk fluid temperature, when the fluid is in liquid state, i.e. at low pressures, the value of the shear strength of the fluid is insensitive to the variation of the pressure of the fluid and is low: when the fluid is in solidification state, i.e. at medium and high but not extremely high pressures, the value of the shear strength of the fluid is the most sensitive to the variation of the pressure of the fluid and is very approximately linearly increased with the increase of the pressure of the fluid; when the fluid is in high solidification state, i.e. at extremely high pressures, the value of the shear strength of the fluid is insensitive to the variation of the pressure of the fluid and is the highest, i.e. approaches the value of the shear strength of the fluid in solid state.

Extends one's knowledge of the shear strength of a fluid in the while ranges of pressure and temperature.

The problem of cyclic variation has been an interesting area of research and has been investigated by many researchers. It is more severe in the case of two‐stroke engines compared with four‐stroke engines. One of the reasons for these cycle‐to‐cycle variations is the variations in the air‐fuel ratios of individual cycles and, if these values of individual cycle air‐fuel ratios are available by some means, they can be used for controlling the cyclic variations. The purpose of this paper is to find a technique to predict the air‐fuel ratio of the individual cycles and use the same for reducing cyclic variations.

In this work, a neuro‐fuzzy model was developed using MATLAB software to compute the air‐fuel ratio of the individual cycles based on the relationship between the air‐fuel ratio and the combustion parameters such as those indicating mean effective pressure (IMEP), crank angle occurrence of peak pressure, and angles of different percentages of heat releases. In‐cylinder pressure traces of 1,000 continuous cycles were measured using a Personal Computer (PC)‐based data acquisition system and an investigation was carried out. The readings were taken for two modes of operations, namely gasoline carburetion and electronic gasoline injection. The engine was loaded by an eddy current dynamometer. The air‐fuel ratio was varied from rich to lean by adjusting the fuel quantity in the carburetion mode and adjusting the pulse width (measure of quantity of fuel to be injected) in the injection mode, at constant throttle. The cyclic variation was identified by the variations in the peak pressures and IMEPs of the individual cycles. The stored data were given as input to the developed neuro‐fuzzy model and, using SIMULINK, the air‐fuel ratios of individual cycles were obtained. These predicted values are fed to the electronic control module (ECM) (meant for injecting the fuel) for refining the pulse width to get cyclic variations reduced.

Results show that cyclic variation increases when the mixture becomes lean. It was also found that cyclic variation in an injected engine was less in comparison with the carbureted engine, as the precise control of air‐fuel mixture was possible in the case of the injected engine.

The technique used in this work may be modified to give more precise pulse width by incorporating various other parameters like exhaust temperature, etc. Future research may be focused to incorporate this system in a moving vehicle to get more fuel efficiency and fewer emissions.

The design of vehicle and engine should be slightly modified to incorporate the ECM and various sensors.

The originality in this paper is that a new technique was developed to find the air‐fuel ratio of individual cycles. This will be useful for the engine manufacturers and for those researchers doing research on the engine side.

The mixing of fuel and air plays a pivotal role in enhancing combustion in supersonic regime. Proper mixing stabilizes the flame and prevents blow-off. Blow-off is due to the shorter residence time of fuel and air in the combustor, as the flow is in supersonic regime. The flame is initiated in the local subsonic region created using a flameholder within the supersonic combustor. This study aims to design an effective flameholder which increases the residence time of fuel in the combustor allowing proper combustion preventing blow-off and other instabilities.

The geometry of the strut-based flameholder is altered in the present study to induce a streamwise motion of the fluid downstream of the strut. The streamwise motion of the fluid is initiated by the ramps and grooves of the strut geometry. The numerical simulations were carried out using ANSYS Fluent and are validated against the available experimental and numerical results of cold flow with hydrogen injection using plain strut as the flameholder. In the present study, numerical investigations are performed to analyse the effect on hydrogen injection in strut-based flameholders with ramps and converging grooves using Reynolds-averaged Navier–Stokes equation coupled with Menter’s shear stress transport k-ω turbulence model. The analysis is done to determine the effect of geometrical parameters and flow parameter on the flow structures near the base of the strut where thorough mixing takes place. The geometrical parameters under consideration include the ramp length, groove convergence angle, depth of the groove, groove compression angle and the Mach number. Two different strut configurations, namely, symmetric and asymmetric struts were also studied.

Higher turbulence and complex flow structures are visible in asymmetric strut configuration which develops better mixing of hydrogen and air compared to symmetric strut configuration. The variation in the geometric parameters develop changes in the fluid motion downstream of the strut. The fluid passing through the converging grooves gets decelerated thereby reducing the Mach number by 20% near the base of the strut compared to the straight grooved strut. The shorter ramps are found to be more effective, as the pressure variation in lateral direction is carried along the strut walls downstream of the strut increasing the streamwise motion of the fluid. The decrease in the depth of the groove increases the recirculation zone downstream of the strut. Moreover, the increase in the groove compression angle also increases the turbulence near the base of the strut where the fuel is injected. Variation in the injection port location increases the mixing performance of the combustor by 25%. The turbulence of the fuel jet stream is considerably changed by the increase in the injection velocity. However, the change in the flow field properties within the flow domain is marginal. The increase in fuel mass flow rate brings about considerable change in the flow field inducing stronger shock structures.

The present study identifies the optimum geometry of the strut-based flameholder with ramps and converging grooves. The reaction flow modelling may be performed on the strut geometry incorporating the design features obtained in the present study.

This paper aims to present a detailed analysis to explore the various properties of non-Newtonian couple stress lubricants between parallel porous plates.

With reference to the theories based on micro-continuum analysis, a non-linear, non-Newtonian Reynolds type equation is arrived. The closed form solutions obtained clearly indicate the changes in pressure, load bearing capacity and response time because of variation in viscosity of couple stress fluid.

It is observed that the viscosity variation factor greatly influences the change in pressure, load carrying capacity and squeezing time.

It is observed that the nature of lubricants with suitable additives greatly helps in overcoming the adverse effect because of porous surface. Reynolds type equation is analysed using appropriate boundary conditions. The expression for pressure distribution arrived at in turn leads to the analysis of load bearing capacity and response time.

In this paper, the performance simulation of a vortex controlled diffuser (VCD) has been carried out in low Reynolds number regime. The two‐dimensional steady differential equations for conservation of mass and momentum has been solved for the Reynolds number ranging from 20 to 100, aspect ratio for 2 and 4, and bleed fraction for 2 per cent, 5 per cent and 10 per cent. The effect of each variable on the diffuser efficiency and the stagnation pressure has been studied in detail. From the study, it has been revealed that when the bleed is incorporated, the VCD behaves in a completely different manner from that of a sudden expansion as far as the variation of total pressure along the diffuser is concerned. For a given Reynolds number and aspect ratio, the diffuser efficiency has been noted to be increasing with increase in bleed fraction. VCD with an area ratio of around two has been found to be most suitable. The top corner has been noted to be the most desirable location of the bleed slot for the best performance of the VCD for the considered Reynolds number regime.

This paper investigates the pressure variations on the steel shafts on the journal bearing system with low temperature and variable speed. This paper mainly consist of two parts, experimental and simulation. In the experimental work, journal bearing system is tested with different shafts speed and temperature conditions. The temperature of the system's working conditions was under minus. The collected experimental data such as pressure variations are employed as training and testing data for an artificial neural network. The neural network is a feed forward three layered network. Quick propagation algorithm is used to update the weight of the network during the training. Finally, neural network predictor has superior performance for modelling journal bearing systems with load disturbances.

This paper aims to investigate and understand the fluid mechanics of piezometer rings, a device frequently encountered in engineering practice.

The investigation, implemented by numerical simulation, is based on turbulent flow in a pipe with a 90-degree bend. The pipe Reynolds numbers ranged from approximately 50,000 to 200,000. Two rings, with different dimensions, were investigated. Each ring consisted of four radially deployed straight segments of tubing which connect the pipe to a surrounding circular ring. The interconnections between the pipe and the ring were situated at 90-degree intervals around the circumference of the pipe.

The focus was directed to optimal circumferential locations of the radial connections, the optimal circumferential locations for accurate pressure measurements and the pressure drop penalty incurred by the use of a piezometer ring. For both of the investigated piezometer ring configurations, it was found that measurement locations situated just beyond the points of intermediate circumferential pressure variations were suitable for determining accurate values. The pressure drop was seen to increase because of the presence of the ring. For the smaller ring configuration, the increase in relative pressure drop was on the order 15 per cent, whereas the larger ring configuration lead to a 10 per cent increase.

This is the first attempt known to the authors to investigate and understand the fluid mechanics of piezometer rings.

The purpose of this paper is to investigate the distribution characteristics of airflow in mine ventilation suits with different pipeline structures when the human body is bent at various angles. On this basis, the stress points are extracted to investigate the pressure variation of a ventilation suit under different ventilation rates and pipeline structures.

Based on the three-dimensional human body scanner, portable pressure test and other instruments, a human experiment was conducted in an artificial cabin. The study analyzed and compared the distribution characteristics of clearance under three different pipeline structures, as well as the pressure variation of the ventilation suit.

The study found that the clearance in front of two pipeline structures gradually increased in size as the degree of bending increased, and there was minimal clearance in the chest and back. The longitudinal structure exhibits a significant decrease in clearance compared to the spiral structure. The pressure value of the spiral pipeline structure with the same ventilation volume is low, followed by the transverse structure, while the longitudinal structure has the highest pressure value. The increase in clothing pressure value of a spiral pipeline structured ventilation suit with varying ventilation volumes is minimal.

The ventilation suit has a promising future as a type of personal protective equipment for mitigating heat damage in mines. It is of great value to study the pipeline structure of the ventilation suit for human comfort.

The purpose of this paper is to study pressure measurement correlations, as the location of the pressure sensors should enable to capture variation of the drag force depending on the yaw angle and some geometrical modifications.

The present aerodynamical study, performed on a reduced scale mock-up representing a sport utility vehicle, involves both numerical and experimental investigations. Experiments performed in a wind tunnel facility deal with drag and pressure measurements related to the side wind variation. The pressure sensor locations are deduced from wall streamlines computed from large eddy simulation results on the external surfaces of the mock-up.

After validation of the drag coefficient (Cd) values computed with an aerodynamic balance, measurements should only imply pressure tap mounted on the vehicle to perform real driving emission (RDE) tests.

Relation presented in this paper between pressure coefficients measured on a side sensor and the drag coefficient data must enable to better quantify the drag force contribution of a ground vehicle in RDE tests.

This paper aims to perform numerical simulations through different shaped double stenoses in a vascular tube for a better understanding of arterial blood flow patterns, and their possible role during the progression of atherosclerosis. The dynamics of flow features have been studied by wall pressure, streamline contour and wall shear stress distributions for all models.

A finite volume method has been employed to solve the governing equations for the two‐dimensional, steady, laminar flow of an incompressible and Newtonian fluid.

The paper finds that impact of pressure drop, reattachment length and peak wall shear stress at each restriction primarily depends upon percentage of restriction, if restriction spacing is sufficient. The quantum of impact of pressure drop, reattachment length and peak wall shear stress is much effected for smaller restriction spacing. If recirculating bubble of first restriction merges with the recirculating bubble formed behind the second restriction in this smaller restriction spacing. The similar effect of smaller restriction spacing is observed, if Reynolds number increases also.

The effect of different shaped stenoses, restriction spacing and Reynolds number on the flow characteristics has been investigated and the role of all the flow characteristics on the progression of the disease, atherosclerosis, is discussed.