**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**1783

# Search results for: Adverse pressure gradient

##### 1783 Effect of Adverse Pressure Gradient on a Fluctuating Velocity over the Co-Flow Jet Airfoil

**Authors:**
Morteza Mirhosseini,
Amir B. Khoshnevis

**Abstract:**

^{o}and this has due to the jet energized, while the angle of attack 20

^{o}has different. The airfoil cord based Reynolds number has 10

^{5}.

**Keywords:**
Adverse pressure gradient,
fluctuating velocity,
wall jet,
co-flow jet airfoil.

##### 1782 DNS of a Laminar Separation Bubble

**Authors:**
N. K. Singh,
S. Sarkar

**Abstract:**

Direct numerical simulation (DNS) is used to study the evolution of a boundary layer that was laminar initially followed by separation and then reattachment owing to generation of turbulence. This creates a closed region of recirculation, known as the laminar-separation bubble. The present simulation emulates the flow environment encountered in a modern LP turbine blade, where a laminar separation bubble may occur on the suction surface. The unsteady, incompressible three-dimensional (3-D) Navier-Stokes (NS) equations have been solved over a flat plate in the Cartesian coordinates. The adverse pressure gradient, which causes the flow to separate, is created by a boundary condition. The separated shear layer undergoes transition through appearance of ╬ø vortices, stretching of these create longitudinal streaks. Breakdown of the streaks into small and irregular structures makes the flow turbulent downstream.

**Keywords:**
Adverse pressure gradient,
direct numerical simulation,
laminar separation bubble.

##### 1781 Yield Onset of Thermo-Mechanical Loading of FGM Thick Walled Cylindrical Pressure Vessels

**Authors:**
S. Ansari Sadrabadi,
G. H. Rahimi

**Abstract:**

In this paper, thick walled Cylindrical tanks or tubes made of functionally graded material under internal pressure and temperature gradient are studied. Material parameters have been considered as power functions. They play important role in the elastoplastic behavior of these materials. To clarify their role, different materials with different parameters have been used under temperature gradient. Finally, their effect and loading effect have been determined in first yield point. Also, the important role of temperature gradient was also shown. At the end the study has been results obtained from changes in the elastic modulus and yield stress. Also special attention is also given to the effects of this internal pressure and temperature gradient in the creation of tensile and compressive stresses.

**Keywords:**
FGM,
Cylindrical pressure tubes,
Small deformation
theory,
Yield onset,
Thermal loading.

##### 1780 Unsteady Poiseuille Flow of an Incompressible Elastico-Viscous Fluid in a Tube of Spherical Cross Section on a Porous Boundary

**Authors:**
Sanjay Baburao Kulkarni

**Abstract:**

Exact solution of an unsteady flow of elastico-viscous fluid through a porous media in a tube of spherical cross section under the influence of constant pressure gradient has been obtained in this paper. Initially, the flow is generated by a constant pressure gradient. After attaining the steady state, the pressure gradient is suddenly withdrawn and the resulting fluid motion in a tube of spherical cross section by taking into account of the porosity factor of the bounding surface is investigated. The problem is solved in twostages the first stage is a steady motion in tube under the influence of a constant pressure gradient, the second stage concern with an unsteady motion. The problem is solved employing separation of variables technique. The results are expressed in terms of a nondimensional porosity parameter (K) and elastico-viscosity parameter (β), which depends on the Non-Newtonian coefficient. The flow parameters are found to be identical with that of Newtonian case as elastic-viscosity parameter tends to zero and porosity tends to infinity. It is seen that the effect of elastico-viscosity parameter, porosity parameter of the bounding surface has significant effect on the velocity parameter.

**Keywords:**
Elastico-viscous fluid,
Porous media,
Second order
fluids,
Spherical cross-section.

##### 1779 Unsteady Flow of an Incompressible Elastico-Viscous Fluid of Second order Type in Tube of Ellipsoidal Cross Section on a Porous Boundary

**Authors:**
Sanjay Baburao Kulkarni

**Abstract:**

Exact solution of an unsteady flow of elastico-viscous fluid through a porous media in a tube of ellipsoidal cross section under the influence of constant pressure gradient has been obtained in this paper. Initially, the flow is generated by a constant pressure gradient. After attaining the steady state, the pressure gradient is suddenly withdrawn and the resulting fluid motion in a tube of ellipsoidal cross section by taking into account of the porosity factor of the bounding surface is investigated. The problem is solved in twostages the first stage is a steady motion in tube under the influence of a constant pressure gradient, the second stage concern with an unsteady motion. The problem is solved employing separation of variables technique. The results are expressed in terms of a nondimensional porosity parameter (K) and elastico-viscosity parameter (β), which depends on the Non-Newtonian coefficient. The flow parameters are found to be identical with that of Newtonian case as elastic-viscosity parameter tends to zero and porosity tends to infinity. It is seen that the effect of elastico-viscosity parameter and the porosity parameter of the bounding surface has significant effect on the velocity parameter.

**Keywords:**
Elastico-viscous fluid,
Ellipsoidal cross-section,
Porous media,
Second order fluids.

##### 1778 Unsteady MHD Flow of an Incompressible Elastico-Viscous Fluid in a Tube of Spherical Cross Section on a Porous Boundary

**Authors:**
Sanjay Baburao Kulkarni

**Abstract:**

Exact solution of an unsteady MHD flow of elasticoviscous fluid through a porous media in a tube of spherical cross section under the influence of magnetic field and constant pressure gradient has been obtained in this paper. Initially, the flow is generated by a constant pressure gradient. After attaining the steady state, the pressure gradient is suddenly withdrawn and the resulting fluid motion in a tube of spherical cross section by taking into account of the porosity factor and magnetic parameter of the bounding surface is investigated. The problem is solved in two-stages the first stage is a steady motion in tube under the influence of a constant pressure gradient, the second stage concern with an unsteady motion. The problem is solved employing separation of variables technique. The results are expressed in terms of a non-dimensional porosity parameter (K), magnetic parameter (m) and elasticoviscosity parameter (β), which depends on the Non-Newtonian coefficient. The flow parameters are found to be identical with that of Newtonian case as elastic-viscosity parameter and magnetic parameter tends to zero and porosity tends to infinity. It is seen that the effect of elastico-viscosity parameter, porosity parameter and magnetic parameter of the bounding surface has significant effect on the velocity parameter.

**Keywords:**
Elastico-viscous fluid,
Porous media,
Second order
fluids,
Spherical cross-section,
Magnetic parameter.

##### 1777 Experimental Measurements of the Mean Flow Field in Wide-Angled Diffusers: A Data Bank Contribution

**Authors:**
Karanja Kibicho,
Anthony Sayers

**Abstract:**

**Keywords:**
Two-dimensional,
wide-angled,
diffuser,
stall,
separated
flows,
subsonic flows,
diffuser flow regimes

##### 1776 Control of Pressure Gradient in the Contraction of a Wind Tunnel

**Authors:**
Dehghan Manshadi M.,
Mirzaei M.,
Soltani M. R.,
Ghorbanian K.

**Abstract:**

**Keywords:**
Contraction,
pressure distribution,
trip strip,
turbulence intensity.

##### 1775 Unsteady Flow of an Incompressible Viscous Electrically Conducting Fluid in Tube of Elliptical Cross Section under the Influence of Magnetic Field

**Authors:**
Sanjay Baburao Kulkarni

**Abstract:**

Exact solution of an unsteady flow of elastico-viscous electrically conducting fluid through a porous media in a tube of elliptical cross section under the influence of constant pressure gradient and magnetic field has been obtained in this paper. Initially, the flow is generated by a constant pressure gradient. After attaining the steady state, the pressure gradient is suddenly withdrawn and the resulting fluid motion in a tube of elliptical cross section by taking into account of the transverse magnetic field and porosity factor of the bounding surface is investigated. The problem is solved in twostages the first stage is a steady motion in tube under the influence of a constant pressure gradient, the second stage concern with an unsteady motion. The problem is solved employing separation of variables technique. The results are expressed in terms of a nondimensional porosity parameter (K), magnetic parameter (m) and elastico-viscosity parameter (β), which depends on the Non- Newtonian coefficient. The flow parameters are found to be identical with that of Newtonian case as elastic-viscosity parameter and magnetic parameter tends to zero and porosity tends to infinity. It is seen that the effect of elastico-viscosity parameter, magnetic parameter and the porosity parameter of the bounding surface has significant effect on the velocity parameter.

**Keywords:**
Elastico-viscous fluid,
Elliptic cross-section,
Porous media,
Second order fluids.

##### 1774 Mathematical Modeling of the Working Principle of Gravity Gradient Instrument

**Authors:**
Danni Cong,
Meiping Wu,
Hua Mu,
Xiaofeng He,
Junxiang Lian,
Juliang Cao,
Shaokun Cai,
Hao Qin

**Abstract:**

**Keywords:**
Gravity gradient,
accelerometer,
gravity gradient sensor,
single-axis rotation modulation.

##### 1773 Simulating Gradient Contour and Mesh of a Scalar Field

**Authors:**
Usman Ali Khan,
Bismah Tariq,
Khalida Raza,
Saima Malik,
Aoun Muhammad

**Abstract:**

**Keywords:**
MATLAB,
Gradient,
Contour,
Scalar Field,
Mesh

##### 1772 Numerical Investigation of Unsteady MHD Flow of Second Order Fluid in a Tube of Elliptical Cross-Section on the Porous Boundary

**Authors:**
S. B. Kulkarni,
Hasim A. Chikte,
V. Murali Mohan

**Abstract:**

**Keywords:**
Elastico-viscous fluid,
Porous media,
Elliptic cross-section,
Magnetic parameter,
Numerical Simulation.

##### 1771 A New Modification of Nonlinear Conjugate Gradient Coefficients with Global Convergence Properties

**Authors:**
Ahmad Alhawarat,
Mustafa Mamat,
Mohd Rivaie,
Ismail Mohd

**Abstract:**

**Keywords:**
Conjugate gradient method,
conjugate gradient
coefficient,
global convergence.

##### 1770 Effect of Non-Newtonian Behavior of Oil Phase on Oil-Water Stratified Flow in a Horizontal Channel

**Authors:**
Satish Kumar Dewangan,
Santosh Kumar Senapati

**Abstract:**

The present work focuses on the investigation of the effect of non-Newtonian behavior on the oil-water stratified flow in a horizontal channel using ANSYS Fluent. Coupled level set and volume of fluid (CLSVOF) has been used to capture the evolving interface assuming unsteady, coaxial flow with constant fluid properties. The diametric variation of oil volume fraction, mixture velocity, total pressure and pressure gradient has been studied. Non-Newtonian behavior of oil has been represented by the power law model in order to investigate the effect of flow behavior index. Stratified flow pattern tends to assume dispersed flow pattern with the change in the behavior of oil to non-Newtonian. The pressure gradient is found to be very much sensitive to the flow behavior index. The findings could be useful in designing the transportation pipe line in petroleum industries.

**Keywords:**
Oil-water stratified flow,
horizontal channel,
CLSVOF,
non–Newtonian behavior.

##### 1769 PIV Investigation into the Evolution of Vortical Structures in the Zero Pressure Gradient Boundary Layer

**Authors:**
Ishtiaq A. Chaudhry,
Zia R. Tahir

**Abstract:**

**Keywords:**
Boundary layer,
synthetic jet actuator,
flow
separation control,
vortical structures.

##### 1768 Research on the Correlation of the Fluctuating Density Gradient of the Compressible Flows

**Authors:**
Yasuo Obikane

**Abstract:**

**Keywords:**
Turbulence Modeling ,
Density Gradient Correlation,
Compressible

##### 1767 Segmentation of Noisy Digital Images with Stochastic Gradient Kernel

**Authors:**
Abhishek Neogi,
Jayesh Verma,
Pinaki Pratim Acharjya

**Abstract:**

**Keywords:**
Image segmentation,
edge Detection,
noisy images,
spatialfilters,
stochastic gradient kernel.

##### 1766 Numerical Investigation of Aerodynamic Analysis on Passenger Vehicle

**Authors:**
Cafer Görkem Pınar,
İlker Coşar,
Serkan Uzun,
Atahan Çelebi,
Mehmet Ali Ersoy,
Ali Pınarbaşı

**Abstract:**

In this study, it was numerically investigated that a 1:1 scale model of the Renault Clio MK4 SW brand vehicle aerodynamic analysis was performed in the commercial computational fluid dynamics (CFD) package program of ANSYS CFX 2021 R1 under steady, subsonic, and 3-D conditions. The model of vehicle used for the analysis was made independent of the number of mesh elements and the k-epsilon turbulence model was applied during the analysis. Results were interpreted as streamlines, pressure gradient, and turbulent kinetic energy contours around the vehicle at 50 km/h and 100 km/h speeds. In addition, the validity of the analysis was decided by comparing the drag coefficient of the vehicle with the values in the literature. As a result, the pressure gradient contours of the taillight of the Renault Clio MK4 SW vehicle were examined and the behavior of the total force at speeds of 50 km/h and 100 km/h was interpreted.

**Keywords:**
CFD,
k-epsilon,
aerodynamics,
drag coefficient,
taillight.

##### 1765 Dynamic Measurement System Modeling with Machine Learning Algorithms

**Authors:**
Changqiao Wu,
Guoqing Ding,
Xin Chen

**Abstract:**

**Keywords:**
Dynamic system modeling,
neural network,
normal
equation,
second order gradient descent.

##### 1764 Green Function and Eshelby Tensor Based on Mindlin’s 2nd Gradient Model: An Explicit Study of Spherical Inclusion Case

**Authors:**
A. Selmi,
A. Bisharat

**Abstract:**

Using Fourier transform and based on the Mindlin's 2^{nd} gradient model that involves two length scale parameters, the Green's function, the Eshelby tensor, and the Eshelby-like tensor for a spherical inclusion are derived. It is proved that the Eshelby tensor consists of two parts; the classical Eshelby tensor and a gradient part including the length scale parameters which enable the interpretation of the size effect. When the strain gradient is not taken into account, the obtained Green's function and Eshelby tensor reduce to its analogue based on the classical elasticity. The Eshelby tensor in and outside the inclusion, the volume average of the gradient part and the Eshelby-like tensor are explicitly obtained. Unlike the classical Eshelby tensor, the results show that the components of the new Eshelby tensor vary with the position and the inclusion dimensions. It is demonstrated that the contribution of the gradient part should not be neglected.

**Keywords:**
Eshelby tensor,
Eshelby-like tensor,
Green’s function,
Mindlin’s 2nd gradient model,
Spherical inclusion.

##### 1763 Flexural Strength Design of RC Beams with Consideration of Strain Gradient Effect

**Authors:**
Mantai Chen,
Johnny Ching Ming Ho

**Abstract:**

The stress-strain relationship of concrete under flexure is one of the essential parameters in assessing ultimate flexural strength capacity of RC beams. Currently, the concrete stress-strain curve in flexure is obtained by incorporating a constant scale-down factor of 0.85 in the uniaxial stress-strain curve. However, it was revealed that strain gradient would improve the maximum concrete stress under flexure and concrete stress-strain curve is strain gradient dependent. Based on the strain-gradient-dependent concrete stress-strain curve, the investigation of the combined effects of strain gradient and concrete strength on flexural strength of RC beams was extended to high strength concrete up to 100 MPa by theoretical analysis. As an extension and application of the authors’ previous study, a new flexural strength design method incorporating the combined effects of strain gradient and concrete strength is developed. A set of equivalent rectangular concrete stress block parameters is proposed and applied to produce a series of design charts showing that the flexural strength of RC beams are improved with strain gradient effect considered.

**Keywords:**
Beams,
Equivalent concrete stress block,
Flexural strength,
Strain gradient.

##### 1762 Steady State Creep Behavior of Functionally Graded Thick Cylinder

**Authors:**
Tejeet Singh,
Harmanjit Singh

**Abstract:**

Creep behavior of thick-walled functionally graded cylinder consisting of AlSiC and subjected to internal pressure and high temperature has been analyzed. The functional relationship between strain rate with stress can be described by the well known threshold stress based creep law with a stress exponent of five. The effect of imposing non-linear particle gradient on the distribution of creep stresses in the thick-walled functionally graded composite cylinder has been investigated. The study revealed that for the assumed non-linear particle distribution, the radial stress decreases throughout the cylinder, whereas the tangential, axial and effective stresses have averaging effect. The strain rates in the functionally graded composite cylinder could be reduced to significant extent by employing non-linear gradient in the distribution of reinforcement.

**Keywords:**
Functionally Graded Material,
Pressure,
Steady State Creep,
Thick-Cylinder.

##### 1761 Learning Flexible Neural Networks for Pattern Recognition

**Authors:**
A. Mirzaaghazadeh,
H. Motameni,
M. Karshenas,
H. Nematzadeh

**Abstract:**

**Keywords:**
Back propagation,
Flexible,
Gradient,
Learning,
Neural network,
Pattern recognition.

##### 1760 Hybrid Gravity Gradient Inversion-Ant Colony Optimization Algorithm for Motion Planning of Mobile Robots

**Authors:**
Meng Wu

**Abstract:**

Motion planning is a common task required to be fulfilled by robots. A strategy combining Ant Colony Optimization (ACO) and gravity gradient inversion algorithm is proposed for motion planning of mobile robots. In this paper, in order to realize optimal motion planning strategy, the cost function in ACO is designed based on gravity gradient inversion algorithm. The obstacles around mobile robot can cause gravity gradient anomalies; the gradiometer is installed on the mobile robot to detect the gravity gradient anomalies. After obtaining the anomalies, gravity gradient inversion algorithm is employed to calculate relative distance and orientation between mobile robot and obstacles. The relative distance and orientation deduced from gravity gradient inversion algorithm is employed as cost function in ACO algorithm to realize motion planning. The proposed strategy is validated by the simulation and experiment results.

**Keywords:**
Motion planning,
gravity gradient inversion algorithm,
ant colony optimization.

##### 1759 Impact of Viscous and Heat Relaxation Loss on the Critical Temperature Gradients of Thermoacoustic Stacks

**Authors:**
Zhibin Yu,
Artur J. Jaworski,
Abdulrahman S. Abduljalil

**Abstract:**

**Keywords:**
Critical temperature gradient,
heat relaxation,
stack,
viscous effect.

##### 1758 Flow of a Second Order Fluid through Constricted Tube with Slip Velocity at Wall Using Integral Method

**Authors:**
Nosheen Zareen Khan,
Abdul Majeed Siddiqui,
Muhammad Afzal Rana

**Abstract:**

**Keywords:**
Approximate solution,
constricted tube,
non-Newtonian fluids,
Reynolds number.

##### 1757 Pressure Losses on Realistic Geometry of Tracheobronchial Tree

**Authors:**
Michaela Chovancova,
Jakub Elcner

**Abstract:**

Real bronchial tree is very complicated piping system. Analysis of flow and pressure losses in this system is very difficult. Due to the complex geometry and the very small size in the lower generations is examination by CFD possible only in the central part of bronchial tree. For specify the pressure losses of lower generations is necessary to provide a mathematical equation. Determination of mathematical formulas for calculation of pressure losses in the real lungs is time consuming and inefficient process due to its complexity and diversity. For these calculations is necessary to slightly simplify the geometry of lungs (same cross-section over the length of individual generation) or use one of the idealized models of lungs (Horsfield, Weibel). The article compares the values of pressure losses obtained from CFD simulation of air flow in the central part of the real bronchial tree with the values calculated in a slightly simplified real lungs by using a mathematical relationship derived from the Bernoulli and continuity equations. The aim of the article is to analyse the accuracy of the analytical method and its possibility of use for the calculation of pressure losses in lower generations, which is difficult to solve by numerical method due to the small geometry.

**Keywords:**
Pressure gradient,
airways resistance,
real geometry
of bronchial tree,
breathing.

##### 1756 Numerical Modeling of Flow in USBR II Stilling Basin with End Adverse Slope

**Authors:**
Hamidreza Babaali,
Alireza Mojtahedi,
Nasim Soori,
Saba Soori

**Abstract:**

Hydraulic jump is one of the effective ways of energy dissipation in stilling basins that the energy is highly dissipated by jumping. Adverse slope surface at the end stilling basin is caused to increase energy dissipation and stability of the hydraulic jump. In this study, the adverse slope has been added to end of United States Bureau of Reclamation (USBR) II stilling basin in hydraulic model of Nazloochay dam with scale 1:40, and flow simulated into stilling basin using Flow-3D software. The numerical model is verified by experimental data of water depth in stilling basin. Then, the parameters of water level profile, Froude Number, pressure, air entrainment and turbulent dissipation investigated for discharging 300 m^{3}/s using K-Ɛ and Re-Normalization Group (RNG) turbulence models. The results showed a good agreement between numerical and experimental model as numerical model can be used to optimize of stilling basins.

**Keywords:**
Experimental and numerical modeling,
end adverse slope,
flow parameters,
USBR II Stilling Basin.

##### 1755 A Refined Nonlocal Strain Gradient Theory for Assessing Scaling-Dependent Vibration Behavior of Microbeams

**Authors:**
Xiaobai Li,
Li Li,
Yujin Hu,
Weiming Deng,
Zhe Ding

**Abstract:**

**Keywords:**
Euler-Bernoulli Beams,
free vibration,
higher order
inertia,
nonlocal strain gradient theory,
velocity gradient.

##### 1754 Comparison of Three Versions of Conjugate Gradient Method in Predicting an Unknown Irregular Boundary Profile

**Authors:**
V. Ghadamyari,
F. Samadi,
F. Kowsary

**Abstract:**

**Keywords:**
Boundary elements,
Conjugate Gradient Method,
Inverse Geometry Problem,
Sensitivity equation.