BlockMesh Drill Down Challenge

here is the ggogle drive link of all the pics of Mesh.
with 0.2 ,0.5 and 0.8 grading factor


https://drive.google.com/open?id=1i0mj6-z5xErixg_PI-7eqwGYM0_WTG3w


from the figure it is quite clear as we increase
the grading factor near the wall increases number
cell near the wall decrease blockMesh files are
provided in the other link..

Results obtained:
                 Simulation is carried out using icoFoam
                 solver below is the tables
        mesh grade     deltaT    Courant number 
        0.2            1e-5       0.0899732
        0.5            1e-5       0.320432
        0.8            1e-5       0.498130


    For different grading factor same deltaT was choosen to achieve the 
    convergence this is obtained only when courant no is les than 1.
    As time increases courant no may go above 1 and lead to divergence
    but it can be controlled by changing deltaT
    time was same for all the three cases
    below is the simulation result..the result was almost same
    for all the thre cases

    https://drive.google.com/open?id=19uutSNF5-k2r16Pc_fYiAzlrqhlLm1MY
    
     here is the google drive link of velocity of different meshes  
     and velocity at 0.085m from the inlet
     
    https://drive.google.com/open?id=1VjCoLD6XN49Lk6vccKqk35s8h-XzROXj
    from the figure it is quite clear that 0.2 mesh
    has more finer and smooth graph as 
    compared to the other two although theis is not
    much difference this is beacause
    0.2 has more cell near the wall as compared 
    to 0.5 and 0.8
    
    

backward facing step

the simulation is done using icoFoam solver with initial velocity of 1 m/s for three different mesh grading factor near the wall

Mesh in x direction 200 cells

in y direction 10

the openfoam simulation of backward facing step is done using.
icoFoam solver the velocity profile is analyzed
for different mesh grading factor 


here is the google drive link of all the blockmesh 
of 0.2 ,0.5 and 0.8 grading factor with velocity 
presure and controldict file

https://drive.google.com/open?id=1kLYQnyBvLIoEAq_nhhLy2Vg_B5mB8FH_