Challenge

Week 2 - Flow over a Cylinder.

MMohammed Dhukka24 Sept 2021

AIM

FLOW OVER THE CYLINDER SHOWING IN TWO-DIMENSIONAL SYMMETRY FORM,

INTRODUCTION AND THORY OF TOPIC

TO SHOW THE VORTEX KARMAN STREET THEORY, BEHAVIOUR OF VORTEX SHADING AROUND AND OUTSIDE OF CYLINDER, IN LAMINAR FLOW OR LOW RAYNOLD NUMBER FLOW, IT GIVESBEHAVIOUR OF VORTEX, AS SHOWN IN SIMULATED RESULT,

Re: 100

SHOWN STEADY AND UNSTEADY FLOW

INSTEADY, GIVEN VORTEX BEHIND OF CYLINDER,

UNSTEADY, GIVEN VORTEX BEHIND OF CYLINDER BY CONSIDERING TRINSENT SIMULATION, RESULT OF STROUHAL NUMBER, IN UNSTEADY FOLW IS NOT CONSTENT WITH RWSPECT TO TIME,

IMPORTANCE

FOR CALCULATION IN AERODYNAMIC FOR PRODUCING LIFT AND DRAG
FLOW OF RESULT HELPS IN STUDY OF FLOW IN AIRFOIL IN AVIATION INDUSTRY FOR CALCULATION OF LIFT AND DRAG
SHOW THE FLOW SEPARATION LOW LAMINAR FLOW
SHOW INCREASE IN VELOCITY ON UPPER FACE AND DECREASE IN CENTRE POINT, CALLED STAGNATION POINT, STAGNATION POINT WHER VELOCITY IS ZERO.
AT LOW RE, THRE IS NO FLOW SEPARATION IS SEEN ON SURFACE, AT VERY HIGH VELOCTY IT SHOW FLOW SEPARATION DUE TO PRESSURE GRADIENT
IT USED FOR CALCULATION OF PRESSURE GRADIENT ON AIR FOIL, CALCULATING THE UPPER AND LOWER PRESSURE ON AIR FOIL, EFFECTIVENESS OF LIFT PRODUCE BY AIRFOIL OF DIFFERENT SHAPE
IT USED IN AUTOMOBILE INDUSTRIES FOR CAR BODY SHAPE FOR STREAMLINE,
FOR TRAIN AND BULLET TRAIN, HYPER LOOP, AREODYNAMIC CALCULTIONS
USED IN CONSIDERATION HIGH MACH NO OF ROCKETS AND MISSILES,
TO MAKE FLOW OF HIGH-SPEED BOUNDARY LAYER ON MISSILES SURFACE.

SOLVING AND MODELLING

Solution made for steady and unsteady flow

Calculated velocity and pressure at both for monitor point,

Velocity contour, pressure contour and residual curve is attached

Solve at 800 iterations

The Strouhal Number can be expressed as

St = ω l / v where

St = Strouhal Number

ω = oscillation frequency

l = characteristic length

v = flow velocity

Strouhal Number is 0.1

FLOW IS CONVERGED

ALL THE RESIDUAL CURVE IS SHOWING CONVERGENT, BENDING TOWARD THE X AXIS, NOT GOING UPWARD THORUGH OUT SOLUTION, GOES DOWN FROM INITIAL POSITION IN STEADY FORM, ALL OTHER CURVE IS CONVERGED

CALCULATION OF CL AND CD IS SIMULATED ON Re 10 ,100, 1000,10000,100000

PHOTOS AND OF BOTH IS ATTACHED

AS SEEN COEFFICIENT OF LIFT DECREASE WITH INCREASE IN Re NUMBER and

COEFFICIENT OF DRAG IS INCREASE WITH THE INCREASE OF Re NUMBER

CONCLUSION

AT LOW AND MEDIUM Re FLOW IS ATTACHED TO THE SURFACE OF CYLINDER

AT HIGH Re FLOW IS SEPARATION IS SEEN AT BACK SIDE OF CYLINDER

VORTEX IS SEEN OF SMOOTH TYPE AT LOW AND MEDIUM RE

VORTEX IS SEEN UNSTEADY AND INTERMITTANT, LIKE SEPARATED FROM SURFACE AT HIGH Re .

vortex average at Re 100