# Shared Flashcard Set

## Details

Fluid
fluid dynamics UIS
57
Physics
11/25/2015

Term
 what does the karman reduce to flat plate
Definition
 Cf=2(dTheta/dx)
Term
 Mechanics
Definition
 Stationary and Moving bodies under influences of F
Term
 Statics
Definition
 Branch of mechanics that deals with bodies at REST
Term
 Dynamics
Definition
 Branch of mechanics that deal with bodies in motion
Term
 Fluid mechanics
Definition
 behavior of fluids in motion or at rest and their interaction with solids or other boundaries
Term
 Flyid dynamics
Definition
 Same as FM, but sets fluids at rest to V=0
Term
 Hydrodanamics
Definition
 Study of motion of fluids that can be approx as INCOMPRESSOBLE
Term
 Nu
Definition
 Nusselt number = convection heat transfer/conduction heat transfer =hL/k
Term
 solid vs fluid
Definition
 a fluid always deforms under shear stress
Term
 Stress vs strain
Definition
 Stress and strain is proportional in solids, but in fluid, stress is proportional to strain rate
Term
 Stress
Definition
 Force per unit area
Term
 Normal stress
Definition
 Normal force over area
Term
 Shear stress
Definition
 Tangent force / Area
Term
 Pressure P in relation to stress
Definition
 P is normal stress in fluid at rest
Term
 GAS vs LIQUID wict filling space
Definition
 gas fills entire available space, liquid forms free surface
Term
 No slip condition
Definition
 Fluid sticks to solid surface - forms boundary layer due to viscocity
Term
 Viscous vs Inviscid regions of flow
Definition
 visc - flows in which friction effects are significantinvisc - viscos forces are nigligibly small compared to inertial or pressure forces
Term
 Flow speed in form of Ma and incompressible approx
Definition
 Ma = V/c - approx inc if Ma < 0,3 this is because that usually approx less that 5% density change
Term
Definition
 Steady - no change at a point w/time
Term
 Uniform flow
Definition
 No change with location over specified region
Term
 System
Definition
 quantity of matter or region in space chosen to study
Term
 Surrounding
Definition
 The mass or region outside the system
Term
 Boundary
Definition
 real or imaginary surface that separates the system from the surrounding (either fixed or movable
Term
 closed system
Definition
 fixed amount of mass, no mass accross boundary
Term
 Open system
Definition
 Properly selected region in space
Term
 speed of sound for ideal gas
Definition
 c=squareroot(kRT)
Term
 viscoucity def/forklaring
Definition
 resistance to deformation
Term
 Newtonian fluids
Definition
 Deformation is proportional to shear stress
Term
 Viscocity in liquids vs gases IRT temp
Definition
 visc down when temp up for liquids, up when temp up for gasses.
Term
 Streamline
Definition
 "a curve that is everywhere tangent to the instantanious local velocity vector" For steady, incomp 2d: u=(dY/dy) v=-(dY/dx)
Term
 pathline
Definition
 follow path of one particle over a time period
Term
 Streakline
Definition
 Insert several particles and take instantanious pic
Term
 Steady flow IRT stream, path and streakline
Definition
 all the same when flow is steady
Term
 Timeline
Definition
 YO - hydrogen
Term
 Rate of heat transfer for flat plate
Definition
 Q=hA(deltaT)
Term
 Contour plot
Definition
 curves of constant scalar properties
Term
 Creeing flow approx
Definition
 Re<<<1
Term
 Inviscid region of flow (when to approx)
Definition
 SPØR JERRY
Term
 Continuiry eq
Definition
 for steady incomp flow - (du/dx)+(dv/dy)+(dw/dz)=0
Term
 When can you use stream and potential function?
Definition
Term
 What is friction force equal to on flat plate?
Definition
 Same as Tw*A (because Tw=(Ft/A))
Term
 what is h
Definition
 h is equal to heat transfer coefficient
Term
 Tau - what is this equal to (in terms of differential)?
Definition
 Tau = my(du/dy)
Term
 translation, rotation, linear strain shear strain
Definition
 tenk figurer
Term
 Why do we use nondim navier stokes?
Definition
 to see relative effects of terms, and where one or more overpowers the other terms
Term
 what is the Modified reynolds analogy
Definition
 It allows you to calculate heat transfer coeff from knowledge of friction.
Term
 what is residual in CFD context
Definition
 it is a measure of how much our variables differ from the exact solutions. -put all terms on one side, the difference from zero is residual.
Term
 initial conditions CFD
Definition
 starting point to get to a solutions. wrong in the beginning, but get more and more correct as we iterate.
Term
 Itteration in CFD
Definition
 numerical method of marching towards solution
Term
 Cenverging in CFD
Definition
 solution converges to true value (not necessarilly)
Term
 volume flow rate through pipe
Definition
 V'=integral(0-2pi)integral(0-R)(u(r)*r)dr(d(theta)=2pi*integral(0-R)(u(r)*r)drflrste integralet blir 2pi, husk å gange med r på nste integral.
Term
 Hva må du huske når du tar med tyngdekraft i navier stokes?
Definition
 Tyngdekraften fungerer som en dP/dy- altså navier stokes forkortes til dP/dy = rho*gy
Term
 Reynolds analogy limitations
Definition
 limted to flows of fluid with prantl near unity such as gases and negiligable pressure gradient in flow direction
Term
 Hva gjør du for å finne pressure field for u og v?
Definition
 1 - sjekk for continuity2 -kort ned navier stokes - finn deretter dP/dx fra x momentun og deretter dP/dy fra y momentum. 3 sjekk for smooth function!! dP/(dxdy) skal være lik dP(dydx) - dersom dette ikke stemmer er det ikke smooth function, og vi kan ikke fortsette
Term
 boundary conditions for oil film wall
Definition
 dv/dx = 0 ved x lik h! gå tilbake til dv/dx og sett inn x lik h - løs for C1
Term
 hvordan kan du bevise at en fartsprofil bare er funsksjon av en variabel tidlig?
Definition
 Sett inn i continuity equation - så står du igjen med kun f.eks. du/dx=0 - som sier at u bare er funksjon av x
Term
 Can wald interval be trusted? when?
Definition
 Helst høy n - en dersom distibusjonen er normal eller approx normal kan vi stole på den d også
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