InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
For which of these flows, periodic or cyclic boundary conditions are applicable?(a) External flow over objects(b) Swirling flow inside a cylindrical furnace(c) Free surface flows(d) Buoyancy driven flowsThis question was addressed to me in final exam.This interesting question is from Boundary Conditions in portion Boundary Conditions of Computational Fluid Dynamics |
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Answer» The correct option is (b) Swirling flow INSIDE a cylindrical furnace |
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| 2. |
Which of these conditions is used to find the velocity component of the boundary while using constant pressure boundary condition?(a) Conservation of angular momentum(b) Conservation of linear momentum(c) Energy conservation(d) ContinuityI had been asked this question in an internship interview.This interesting question is from Boundary Conditions topic in portion Boundary Conditions of Computational Fluid Dynamics |
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Answer» The correct option is (d) Continuity |
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| 3. |
Which of these is true for an impermeable wall?(a) \(\vec{V}=0\) above the surface(b) \(\vec{V}=0\) at the surface(c) \(\vec{V}.\vec{n}=0\) at the surface(d) \(\vec{V}.\vec{n}=0\) above the surfaceThe question was asked by my college professor while I was bunking the class.My query is from Boundary Conditions topic in chapter Boundary Conditions of Computational Fluid Dynamics |
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Answer» Correct choice is (c) \(\vec{V}.\vec{n}=0\) at the surface |
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| 4. |
If we are solving a k-ε model, the values of k and ε _________(a) are either specified or estimated at the inlet(b) are either specified or estimated at the outlet(c) need not be specified or estimated anywhere(d) are not estimatedI have been asked this question in homework.The query is from Boundary Conditions topic in chapter Boundary Conditions of Computational Fluid Dynamics |
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Answer» CORRECT answer is (a) are either SPECIFIED or estimated at the inlet The best explanation: The most accurate solutions can be achieved only if k and ε are specified at the inlet BOUNDARY. However, if it is not possible to provide, CFD CODES can estimate these values using a formula. |
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| 5. |
Usually, in the inlet boundary conditions ___________ are known.(a) gradients of flow properties(b) diffusive fluxes of properties(c) convective fluxes of properties(d) flow propertiesThis question was posed to me at a job interview.The query is from Boundary Conditions in chapter Boundary Conditions of Computational Fluid Dynamics |
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Answer» The CORRECT choice is (d) flow properties |
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| 6. |
What is the shear force of a fluid (velocity \(\vec{u}\)) near the wall for a moving wall (velocity (\(\overrightarrow{u_{wall}}\)))?(a) \(\vec{F}=-\mu\frac{\vec{u}}{\Delta y}\times area\)(b) \(\vec{F}=-\mu\frac{\vec{u}-\overrightarrow{u_{wall}}}{\Delta y}\times area\)(c) \(\vec{F}=-\mu\frac{\vec{u}-\overrightarrow{u_{wall}}}{\Delta y}\)(d) \(\vec{F}=-\mu\frac{\vec{u}}{\Delta y}\)This question was posed to me in an internship interview.This interesting question is from Boundary Conditions in chapter Boundary Conditions of Computational Fluid Dynamics |
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Answer» CORRECT CHOICE is (b) \(\vec{F}=-\mu\frac{\vec{U}-\overrightarrow{u_{wall}}}{\Delta y}\times area\) The explanation: Shear force is a PRODUCT of shear stress and area. Shear stress is defined by NEWTON’s law of viscosity. For moving walls, the relative velocity \(\vec{u}-\overrightarrow{u_{wall}}\) should be taken. Therefore, the shear force is given by \(\vec{F}=-\mu\frac{\vec{u}-\overrightarrow{u_{wall}}}{\Delta y}\times area\). |
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| 7. |
Which of these is the best practice regarding outlet boundaries?(a) Outlet boundaries should be at the exact outlet of the geometry(b) Outlet boundaries should be set as close as possible to the inlet boundaries(c) Outlet boundaries should be set as far as possible to the physical geometry(d) Outlet boundaries should be set as close as possible to the physical geometryThis question was addressed to me in an interview.Question is taken from Boundary Conditions in chapter Boundary Conditions of Computational Fluid Dynamics |
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Answer» Right option is (c) Outlet boundaries should be set as far as POSSIBLE to the physical geometry |
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| 8. |
The diffusive fluxes in the inlet boundary conditions _________(a) are specified(b) can be calculated(c) are not necessary(d) should be approximatedI have been asked this question in semester exam.This is a very interesting question from Boundary Conditions topic in section Boundary Conditions of Computational Fluid Dynamics |
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Answer» Correct answer is (d) should be APPROXIMATED |
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| 9. |
The convective fluxes in the inlet boundary layer _________(a) are specified(b) can be calculated(c) should be approximated(d) are not necessaryThe question was asked in a job interview.The origin of the question is Boundary Conditions topic in division Boundary Conditions of Computational Fluid Dynamics |
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Answer» The CORRECT choice is (B) can be calculated |
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| 10. |
Which of these represents the temperature of the fluid layer immediately near the wall at a condition analogous to no-slip? Note: Tw is the temperature at the wall.(a) T=-1(b) T=1(c) T=Tw(d) T=0The question was posed to me in quiz.Question is taken from Boundary Conditions in chapter Boundary Conditions of Computational Fluid Dynamics |
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Answer» CORRECT CHOICE is (C) T=Tw Easiest explanation: For a condition analogous to no-slip in temperature, the temperature of the fluid LAYER near the wall is the same as the wall temperature. Therefore, T=Tw. |
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| 11. |
Which of these statements is false regarding the pressure correction at boundaries?(a) Pressure reference is set at the inlet boundaries(b) Pressure reference is set at the outlet boundaries(c) The link to the inlet boundary side is suppressed(d) The link to the outlet boundary side is suppressedI got this question during a job interview.This intriguing question comes from Boundary Conditions topic in section Boundary Conditions of Computational Fluid Dynamics |
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Answer» RIGHT answer is (B) PRESSURE reference is set at the outlet boundaries The best I can explain: Pressure reference is set at the inlet boundaries and the link to the inlet SIDE is suppressed. In the outlet boundaries, there is no NEED for setting another reference pressure but the link to the outlet side is suppressed. |
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| 12. |
The Neumann and Dirichlet boundary conditions are _________ and _________ in mathematical terms.(a) value specified, flux specified(b) flux specified, value specified(c) flux specified, gradient specified(d) value specified, time specifiedI got this question in a national level competition.I would like to ask this question from Boundary Conditions in division Boundary Conditions of Computational Fluid Dynamics |
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Answer» Correct option is (b) flux specified, value specified |
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| 13. |
While applying the constant pressure boundary condition, which of these is done?(a) Pressure is set to 0(b) Pressure correction is set to 1(c) Pressure correction is set to zero(d) Pressure is set to 1I had been asked this question in quiz.My question comes from Boundary Conditions in division Boundary Conditions of Computational Fluid Dynamics |
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Answer» RIGHT answer is (c) Pressure correction is set to zero To explain I WOULD say: When CONSTANT pressure BOUNDARY is used, pressure is set to a fixed value which is the boundary pressure value and pressure correction is set to zero. |
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| 14. |
Which is not a type of boundary conditions in CFD?(a) Cyclic boundary conditions(b) Symmetry boundary conditions(c) Wall boundary conditions(d) Nodal boundary conditionsThe question was asked in an interview for internship.This is a very interesting question from Boundary Conditions in portion Boundary Conditions of Computational Fluid Dynamics |
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Answer» CORRECT answer is (d) Nodal boundary conditions The best EXPLANATION: Boundary conditions are not defined at nodes and nodal boundary conditions do not EXIST. There are many types of boundary conditions in CFD. Some of them are Wall boundary conditions Symmetry boundary conditions Inlet boundary conditions Outlet boundary conditions Constant PRESSURE boundary conditions Periodic or cyclic boundary conditions |
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| 15. |
Which is true for a symmetry boundary?(a) Diffusive flux is non-zero(b) Diffusive flux is zero(c) Convective flux is zero(d) Convective flux is non-zeroThe question was posed to me by my college director while I was bunking the class.This is a very interesting question from Boundary Conditions topic in division Boundary Conditions of Computational Fluid Dynamics |
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Answer» Right choice is (c) Convective flux is zero |
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| 16. |
Which among these is a combination of value specified and flux specified boundary conditions?(a) Dirichlet(b) Mixed(c) Neumann(d) SymmetryI have been asked this question by my school teacher while I was bunking the class.This intriguing question comes from Boundary Conditions in section Boundary Conditions of Computational Fluid Dynamics |
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Answer» RIGHT choice is (b) MIXED Explanation: TYPE 3 boundary CONDITIONS are the mixed boundary conditions. Mixed boundary condition combines Neumann and Dirichlet boundary conditions. |
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| 17. |
Constant pressure boundary condition makes the pressure correction cell nearest to the boundaries to act as ____________(a) Source or sink of mass(b) Source or sink of heat(c) Convection cell(d) Diffusion cellI had been asked this question by my school principal while I was bunking the class.Query is from Boundary Conditions in section Boundary Conditions of Computational Fluid Dynamics |
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Answer» Correct option is (a) Source or SINK of mass |
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| 18. |
In Dirichlet boundary conditions, the flux values _________(a) can be calculated(b) are unknowns(c) are known(d) are 0This question was posed to me in an online quiz.This key question is from Boundary Conditions topic in portion Boundary Conditions of Computational Fluid Dynamics |
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Answer» The correct answer is (a) can be calculated |
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| 19. |
Which among these is used to specify a particular problem which we consider for solving in CFD?(a) Boundary conditions(b) Governing equations(c) Governing laws(d) Solution methodThis question was addressed to me during an interview.My enquiry is from Boundary Conditions in division Boundary Conditions of Computational Fluid Dynamics |
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Answer» The correct option is (a) Boundary conditions |
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| 20. |
For cyclic boundary conditions, which of these should be equated?(a) The flow variables(b) Gradient of the flow variables(c) Flux of the flow variables(d) Second derivative of the flow variablesI have been asked this question in semester exam.My doubt is from Boundary Conditions in portion Boundary Conditions of Computational Fluid Dynamics |
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Answer» Correct choice is (c) Flux of the FLOW variables |
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| 21. |
Which of these pose a problem in constant pressure boundaries?(a) Velocity(b) Flow direction(c) Density(d) Heat flux directionThis question was posed to me by my college professor while I was bunking the class.My query is from Boundary Conditions topic in division Boundary Conditions of Computational Fluid Dynamics |
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Answer» CORRECT choice is (b) FLOW DIRECTION To explain: CONSTANT pressure boundaries are USED when the velocity is unknown. The main problem in this is the flow direction. It has to be found while solving the flow properties. |
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| 22. |
For a symmetry boundary, which is correct?(a) Vn≠0, τnn=0(b) Vn≠0, τnn≠0(c) Vn=0, τnn≠0(d) Vn=0, τnn=0I got this question in a job interview.Asked question is from Boundary Conditions in division Boundary Conditions of Computational Fluid Dynamics |
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| 23. |
The mass flux out should be equal to the mass flux in. This is in accordance with _________(a) energy conservation(b) momentum conservation(c) continuity condition(d) flux conservationThis question was posed to me in an interview for internship.The query is from Boundary Conditions topic in division Boundary Conditions of Computational Fluid Dynamics |
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Answer» RIGHT option is (c) continuity condition To explain I would say: The theory of continuity (MASS conservation) states that the inlet and outlet mass fluxes should be the same. So, they are always MATCHED by some EXTERNAL CALCULATIONS. |
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| 24. |
The velocity components in the nodes which are not at the boundary are found using ____________(a) energy equation(b) continuity equation(c) equations of state(d) momentum equationI have been asked this question in an interview.Origin of the question is Boundary Conditions topic in portion Boundary Conditions of Computational Fluid Dynamics |
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Answer» Correct choice is (d) momentum equation |
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| 25. |
Which of these following is used to match the outlet and inlet flow velocities?(a) uN,j = uN-1,j×\(\frac{M_{in}}{M_{out}}\)(b) uN-1,j = uN,j×\(\frac{M_{in}}{M_{out}}\)(c) uN-1,j = uN,j×\(\frac{M_{out}}{M_{in}}\)(d) uN,j = uN-1,j×\(\frac{M_{out}}{M_{in}}\)This question was addressed to me during an interview for a job.I want to ask this question from Boundary Conditions topic in portion Boundary Conditions of Computational Fluid Dynamics |
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Answer» Right choice is (a) uN,J = uN-1,j×\(\frac{M_{in}}{M_{out}}\) |
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| 26. |
An extra grid is used before the physical boundary. What is the use of this grid?(a) To store the inlet boundary values(b) To solve the discretized equation(c) To calculate the inlet boundary values(d) To solve the system analyticallyThe question was posed to me in an online interview.The doubt is from Boundary Conditions topic in section Boundary Conditions of Computational Fluid Dynamics |
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Answer» Right CHOICE is (a) To store the INLET boundary values |
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| 27. |
Which of the following applies to a symmetry boundary?(a) There is no flow and no scalar flux across the boundary(b) There are flow and scalar fluxes across the boundary(c) There is no scalar flux but flow is possible across the boundary(d) There is no flow but scalar flux is possible across the boundaryI got this question during an internship interview.This question is from Boundary Conditions topic in portion Boundary Conditions of Computational Fluid Dynamics |
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Answer» The correct ANSWER is (a) There is no flow and no SCALAR FLUX ACROSS the boundary |
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| 28. |
For no-slip condition, which of these is true regarding the pressure correction equation if the wall is at the bottom?(a) an=0(b) aw=0(c) ae=0(d) as=0I got this question in quiz.Query is from Boundary Conditions topic in division Boundary Conditions of Computational Fluid Dynamics |
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Answer» Correct answer is (d) as=0 |
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| 29. |
Initial conditions are used for __________ problems.(a) time-dependent problems(b) boundary value problems(c) control volume problems(d) finite difference problemsThe question was posed to me in an interview for internship.My doubt stems from Boundary Conditions in portion Boundary Conditions of Computational Fluid Dynamics |
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Answer» Right option is (b) boundary value PROBLEMS |
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| 30. |
The pairing operation can be done for all properties except ___________ of a flow.(a) pressure(b) density(c) velocity components(d) temperatureThe question was asked in an interview.The origin of the question is Boundary Conditions topic in section Boundary Conditions of Computational Fluid Dynamics |
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Answer» The correct OPTION is (C) VELOCITY components |
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| 31. |
For inviscid flows, which is correct immediately near the wall?(a) \(\vec{V} ≠ 0\)(b) \(\vec{V} = 0\)(c) \(\vec{V} > 0\)(d) \(\vec{V} \lt 0\)This question was addressed to me by my school principal while I was bunking the class.The question is from Boundary Conditions topic in division Boundary Conditions of Computational Fluid Dynamics |
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| 32. |
For a no-slip condition which of these about velocity components is true near the wall boundary?(a) u=1, v=0, w=0(b) u=0, v=0, w=0(c) u=0, v=1, w=0(d) u=0, v=0, w=1The question was asked in unit test.This question is from Boundary Conditions topic in portion Boundary Conditions of Computational Fluid Dynamics |
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Answer» The correct CHOICE is (b) u=0, v=0, w=0 |
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| 33. |
When do we use a constant pressure boundary condition?(a) When there is an impermeable boundary(b) When there is constant pressure(c) When we do not know the flow distribution but we know the pressure at the boundaries(d) When we do not know the pressure at the boundariesThe question was posed to me by my school teacher while I was bunking the class.My enquiry is from Boundary Conditions topic in portion Boundary Conditions of Computational Fluid Dynamics |
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Answer» RIGHT option is (C) When we do not know the FLOW distribution but we know the pressure at the boundaries To elaborate: When the flow distribution including velocity are not properly known but the boundary pressures are known, a CONSTANT pressure boundary CONDITION is used. |
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| 34. |
Periodic or cyclic boundary conditions are a type of ____________(a) wall boundary conditions(b) constant pressure boundary conditions(c) inlet boundary conditions(d) symmetry boundary conditionsThis question was posed to me during an online interview.This question is from Boundary Conditions topic in portion Boundary Conditions of Computational Fluid Dynamics |
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Answer» The CORRECT option is (d) SYMMETRY BOUNDARY conditions |
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| 35. |
What are the two major types of boundary conditions?(a) Wall and symmetry(b) Inlet and outlet(c) Dirichlet and Neumann(d) Initial and physicalThe question was asked in an interview.This is a very interesting question from Boundary Conditions in portion Boundary Conditions of Computational Fluid Dynamics |
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Answer» CORRECT choice is (C) Dirichlet and NEUMANN The explanation is: Dirichlet and Neumann boundary CONDITIONS are the two boundary conditions. They are used to define the conditions in the physical boundary of a problem. |
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| 36. |
Which of these is not a combination of Neumann and Dirichlet Boundary conditions?(a) Cauchy boundary conditions(b) Wall boundary conditions(c) Mixed boundary conditions(d) Robin boundary conditionsThe question was posed to me in my homework.This key question is from Boundary Conditions topic in division Boundary Conditions of Computational Fluid Dynamics |
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Answer» Correct option is (B) Wall BOUNDARY CONDITIONS |
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| 37. |
The boundary condition represented in the following diagram is ___________(a) Dirichlet(b) Periodic(c) Neumann(d) AxisymmetricI have been asked this question during an interview for a job.This key question is from Boundary Conditions topic in division Boundary Conditions of Computational Fluid Dynamics |
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Answer» Right answer is (c) Neumann |
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| 38. |
A symmetry boundary is treated the same as a wall boundary for this reason.(a) There is flow across this boundary(b) No convection flux across this boundary(c) There is convection flux across this boundary(d) No flow across this boundaryThe question was posed to me in an international level competition.This key question is from Boundary Conditions topic in portion Boundary Conditions of Computational Fluid Dynamics |
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Answer» The correct answer is (d) No flow across this boundary |
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| 39. |
_________ is fixed at one inlet node and pressure correction is set to _________ in that node.(a) Gauge pressure, one(b) Absolute pressure, one(c) Gauge pressure, zero(d) Absolute pressure, zeroI have been asked this question by my school teacher while I was bunking the class.This interesting question is from Boundary Conditions in chapter Boundary Conditions of Computational Fluid Dynamics |
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Answer» Correct OPTION is (d) Absolute PRESSURE, zero |
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| 40. |
Which of these best define the Dirichlet boundary conditions for the property Φ at a point ‘b’ in a boundary?(a) \(\frac{\partial^3 \Phi}{\partial^3 x}\)(b) \(\frac{\partial^2 \Phi}{\partial^2 x}\)(c) \(\frac{\partial\Phi}{\partial x}\)(d) ΦbI got this question by my school principal while I was bunking the class.My enquiry is from Boundary Conditions in chapter Boundary Conditions of Computational Fluid Dynamics |
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Answer» Correct ANSWER is (d) Φb |
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