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Correct choice is (a) True

For EXPLANATION I would say: The is obtained by constructing a finite difference approximation to the vorticity transport EQUATION on an expanding spherical POLAR grid SYSTEM. Central difference of second order accuracy both in TIME and space is utilized.

Right OPTION is (a) True

Best explanation: The flow is independent of indeed equation CLEARLY shows that the velocity field DEPENDS only on r. such a flow is defined as AXISYMMETRIC flow. Once again, we have a flow with two independent variables with the axisymmetric flow.

The correct answer is (a) False

Explanation: The kutta condition is inapplicable in the case of blunt bodies. For this REASON, a three dimensional source –vorticity METHOD for simulating INCOMPRESSIBLE potential flows AROUND a deforming body without using the kutta condition.

The correct option is (a) True

Explanation: The flow is assumed to be AXISYMMETRIC throughout this range. A timed PENT stream function vorticity formulation is adopted. The SOLUTION is obtained by constructing a finite difference APPROXIMATION to the vorticity transport equation on an expanding spherical polar grid system.

Right option is (b) True

Easiest EXPLANATION: The three dimensional doublet is defined as the strength of the doublet, compare EQUATION with its two dimensional counterpart given in equation. Note that the three dimensional effects LEAD to an inverse SQUARED VARIATION.

Correct ANSWER is (a) 2

Easy explanation: Panel method is generally divided into TWO categories-Surface panel method and mean-surface panel method. Surface panel method is more precise and ACCURATE as the NUMBER of panels can be increased based on the complexity of the BODY.

Right option is (a) True

Easy explanation: The three DIMENSIONAL incompressible POTENTIAL flows around a body accompanied by a wake vortex, surface singularity METHOD have been employed extensively, owing to their ease of use and low SOLUTION times.

The correct choice is (a) Quadrilateral PANELS with constant source strength

The best explanation: In case of panel method, the entire BODY is approximated into several SMALLER quadrilateral panels having constant source strength. Although when the bodies get COMPLEX, higher order panel technique is used, which makes use of curved panels with variable source STRENGTHS.

Right OPTION is (a) True

To EXPLAIN I would say: A three dimensional SOURCE method for simulating incompressible potential FLOWS around a deforming body without the kutta condition. A three dimensional source vorticity method that does not use the kutta condition is proposed.

Correct choice is (c) Incompressible flow

To elaborate: Panel method is IDEA for design ANALYSIS for only incompressible flows. It lacks the ability to model viscous flow, rotational flow w and supersonic flow. A panel method performs best when MODELING fully-attached, high-reynolds-number (> 105), subsonic (Mach number < 1) flow.

Right choice is (d) Both SOURCE and vortex panels

For explanation I would SAY: Unlike non-lifting bodies which makes use of only source PANEL, lifting doies have a distribution of both source and vortex panels to assess the three-dimensional potential flow.

Correct choice is (b) False

To explain I would say: Mean-surface panel METHOD PLACES the panels in the interior side of the body. This results in less accurate results and is only USED for APPROXIMATION. Thus, this method is used for preliminary design instead of final design calculations.

Right CHOICE is (b) Incompressible flow

The explanation: Panel METHOD is a technique that is used to numerically compute the inviscid, incompressible flow around any ARBITRARY BODY. The panel method incorporates laying panels of source/doublet/votices distribution over the body to obtain the aerodynamic properties.

Right choice is (a) True

For EXPLANATION: THREE DIMENSIONAL aerodynamics by considering the simple case of IRROTATIONAL, inviscid flow. When compressibility can also be neglected, we CONSIDER a solution to Laplace’s equation in three dimensional just as in the two dimensional case.

Correct option is (a) True

To ELABORATE: The large EDDY simulation in the regions away from SOLID surfaces. For both the subcritical and supercritical solutions, the AGREEMENT with EXPERIMENTAL measurements for the mean drag and pressure distribution over the sphere is adequate.

The correct choice is (a) True

To explain: The IMPEDANCES are CALCULATED from resistivity values given at the NODE locations and the distances between the nodes. This is analogous to a NETWORK of RESISTORS, were current flows through the branches and the potential are defined at all intersections.

Correct choice is (a) True

To elaborate: The flow field around a SPHERE in a uniform flow has been analyzed NUMERICALLY for conditions corresponding to the subcritical and supercritical regimes spanning a wide range of Reynolds NUMBER PARTICULAR attention has been devoted to assessing PREDICTIONS.

Correct answer is (a) True

The explanation: The distance zero is the absolute magnitudes of the strengths of the source and sinks increases in such a FASHION that product remains constant. This LIMITING process we obtain by a SPECIAL flow pattern defined as a DOUBLET.

Right option is (a) True

To EXPLAIN I would say: The FLOW INDUCED by the three dimensional doublet is a series of STREAM surfaces generated by REVOLVING the streamlines in about the r axis. Compare these stream lines with the two dimensional case illustrated they are qualitatively different.

Right option is (a) Hess and Smith

The best I can explain: In order to model the wing section there were two methods used-Conformal mapping and Airfoil Theory. But these methods were not general and hence basic panel METHOD was DEVELOPED by Hess and Smith at the Douglas Aircraft Co. in the LATE 1950S and early 1960s.

Correct option is (a) Source panel

Easiest EXPLANATION: In case of non-LIFTING bluff bodies, source panels are distributed to ANALYZE the three-dimensional potential FLOW unlike DISTRIBUTION of both vortex and source panels in case of lifting bodies.

Right choice is (b) CURVED panels

The explanation is: Higher-order panel METHOD CAME into being when the panel method became COMPUTATIONALLY demanding for complex bodies. This method makes use of curved panels with variable source strength.

Right choice is (B) True

Explanation: The FLUID is incompressible, homogeneous and its flow is governed by the complete more naive stokes equations. The range of Reynold number studied id 1-1000, where a recirculatory wake appears and the NONLINEAR TERMS are ESSENTIAL.

The correct option is (a) True

To elaborate: Numerical solutions of the transient uniform flow around a sphere are obtained. The transition TAKES place between an initial POTENTIAL flow and a FULLY developed viscous FIELD. The fluid is INCOMPRESSIBLE and homogeneous around the sphere.

The CORRECT ANSWER is (a) True

Best EXPLANATION: The axisymmetric flow is a degenerate three dimensional flow, and it is somewhat misleading to REFER it as the two dimensional, and the axisymmetric flow has only two independent variables, but it EXHIBITS some of the same physical characteristics.

Correct answer is (a) True

To explain I WOULD SAY: The linearized stability analysis due to the large gradients of vorticity in the FIELD. Quantitative physical results are obtained. The geometrical parameters CHARACTERIZING the recirculatory wake COMPARE favorably with those recorded in physical experiments.

The correct option is (a) True

Easy explanation: The THREE dimensional EFFECTS lead to an INVERSE squared variation and INTRODUCE into the two dimensional case. The stream lines of this velocity field are sketched in the FIGURE are the stream lines in the planes.

The correct choice is (B) Dipole

The EXPLANATION is: LIFTING BODIES have a trailing edge which leads to a wake REGION. In the wake region, there is formation of vortices due to the disturbances in the flow. In this region, a dipole or vorticity singularity is used.

The correct answer is (a) True

Easy explanation: In every panel, there is a POINT selected to analyze the FLOW field and to CHECK if the NET sum of contribution from other panel elements is zero. This point is known as the collocation point.

The CORRECT CHOICE is (a) True

Easiest explanation: In two DIMENSIONAL we used sources and VORTICES extensively to construct the flow over an airfoil. In three dimensional we also use sources and vortices to model the flow over the wings and the BODIES. This section shows how this is done.

Correct answer is (a) True

The explanation is: CENTRAL differencing of SECOND order accuracy both in TIME and space is utilized. Experiments with numerical STABILITY show an APPRECIABLE deviation from linearized stability analysis due to the large gradients of vorticity in the field.

The correct option is (a) True

Best explanation: potential and current SOURCE are defined at each NODE. In the three dimensional, each interior node is connected to the six surrounding nodes by impedance branches. POTENTIALS and current SOURCES are defines at each successive nodes.

Right option is (a) True

The explanation is: The velocity potential is obtained by SOLVING a set of simultaneous equations. These ADDED masses are CALCULATED by giving acceleration to the body or the fluid, which helps to solve velocity potential in a set of simultaneous equation.

The correct option is (a) True

Easy explanation: The source and sink are equal but opposite STRENGTH located at points O and A, as sketched.The distance between the source and sink is L. CONSIDER an arbitrary POINT p located a distance r from the sink and a distance from the source, so source and sink are equal but opposite in strength.

Right choice is (b) True

Explanation: As the source and the sink approach as their strengths become INFINITE. That the flow field produced by the EQUATION is a three dimensional DOUBLET. The three dimensional doublet has defined the strength of the doublet with its TWO dimensional.

Correct option is (B) True

To EXPLAIN: The three dimensional incompressible potential flows around a body accompanied by a wake vortex, surface singularity methods have been EMPLOYED EXTENSIVELY owing to their ease of use and low solution times. In the case of vertical flow, the KUTTA condition is applied.

The correct option is (a) True

The explanation is: The axisymmetric FLOW is sometimes labeled as TWO dimensional flow. However, it is quite different from the two dimensional PLANAR flows discussed earlier. In reality, axisymmetric flow is DEGENERATE three dimensional flow.

Correct answer is (a) True

The explanation: The DEGENERATE case of a source sink pair that leads to a singularity called a doublet. The doublet is frequently used in the theory of INCOMPRESSIBLE flow, the PURPOSE of this section is to describe its PROPERTIES.

The correct answer is (b) False

The explanation is: The lifting or vertical cases where the kutta condition cannot be APPLICABLE, a ROTATING sphere in uniform flow and a sphere with a vortex RING are considered. To assess the ACCURACY of the proposed method, the numerical results compared with the analytical solution.