# CFD DATABASE

### Outils du site

datasetmeca:flow2dpastosccylinder1

## 2D flow around an oscillating cylinder - $Re_{H}= 185$

Numerical study based on the publication of Pham et al., Journal of Marine Science and Technology, Vol. 18, No. 3, pp. 361-368 (2010)
The motion of the cylinder is vertical and forced with a sinusoïdal function

Author : Y. Fraigneau CNRS-LIMSI (yann.fraigneau@limsi.fr)
Date : July 2016
Simulation type : DNS (Sunfluidh code)
Location : /DATABASE_2DFLOW_AROUND_OSCILLATING_CYLINDER_DNS
Status : Free access
Data size : ~ 7 Gb

### Simulation settings

#### Referential : cartesian geometry

1. axes :
• x(i) : downstream direction
• y(j) : normal direction
2. origin :
• $x_0= 0$ : centre of the cylinder
• $y_0= 0$ : mid-height

#### Reference scales

• Density : mass density of the fluid ($\rho_0$)
• Length : cylinder diameter ($D$)
• Velocity : velocity at inlet ($U_0$)
• Dynamic viscosity : dynamic viscosity of the fluid ($\mu_0$)
• Reynolds number : $Re_H= \frac{\rho_0.U_0.D}{\mu_0}= 185$
• Strouhal number : $St_0=\frac{f}{f_0}$ (oscillating-cylinder frequency $f$ over vortex-shedding frequency $f_0$ when the cylinder is at rest)
• motion magnitude : $A \times D$ (where A is the motion factor)

#### Non-dimensionalised data

• velocity : $U^*=\frac{U}{U_0}$
• density : $\rho^*= \rho/\rho_0= 1$
• coordinates : $x*=\frac{x}{D}$, $y^*=\frac{y}{D}$

#### Computational domain

1. Domain scope
1. computational domain size
• Downstream direction(x) : $L_x^*= 90.0$ (upward part $L_u= 40$, downward part $L_d=50$)
• Normal direction (y) : $L_y^*= 80.0$
2. Oscillating cylinder (vertical oscillating motion around the mid-height of the domain)
• centre position at rest : $x_c= 0.0$ and $y_c= 0.0$
• diameter: $D^*= 1$
• oscillation frequency : $St= 0.95$ or $St= 1.2$
• The cylinder is modeled with a pseudo-penalisation method (Pasquetti et al., Applied Numerical Mathematics, 2008)
2. Boundary conditions
• Inlet : imposed pressure uniform velocity ($U_0=1$)
• Outlet : Orlansky type
• Bottom and top conditions : symmetry
3. Spatial resolution
• mesh size : $480 \times 480$ (576.000 cells)
• $\Delta x*$ : from $0.0125$ to $0.78785$$(downstream direction) •$\Delta y*$: from$0.0125$to$0.65924$(normal direction) ### Data features • Time series • from probes • Physical quantities : velocity components along x and y directions (u,v) and pressure (p) • 1 probe • Time step=$2 \,10^{-2}$time unit • Time range : 400 to 600 time units • Location : Xi= 3.5 , Xj=0.0 • File name (per physical quantity): x_ins_00000.d with x= u,v,p • about cylinder motion • center position as a function of time (ASCII file ibm_position01.dat) • cylinder velocity as a function of time (ASCII file ibm_velocity01.dat) • global force components applied to the cylinder (ASCII file ibm_force01.dat) • force contributions exerted on the moving cylinder (ASCII file ibm_force_contribution01.dat, the four last columns can be ignored) • 3D snapshots • Instantaneous fields : velocity components in x, y and z directions (U,V), the pressure (P) and the phase function related to the body motion (TRACE) • Recording rate : 0.4 time unit • Time range from from 200.0 to 600.0 time units • File name : res_xxxxx_yyyyyyy.d • MPI subdomain ID: 0 • Time ID : from 3 to 502 ### Database organisation Data size : ~ 7 Gb Main directory : /vol/DATABASE_MECA/DATABASE_2DFLOW_AROUND_OSCILLATING_CYLINDER_DNS For more details about files, see the wiki doc of Sunfluidh Intermediate directories (four cases of study) •$St= 0.95$and$A= 0.2$- directory : CAS_F0.95_A0.2 •$St= 0.95$and$A= 0.5$- directory : CAS_F0.95_A0.5 •$St= 1.20$and$A= 0.2$- directory : CAS_F1.2_A0.2 •$St= 1.20$and$A= 0.5\$ - directory : CAS_F1.2_A0.5

Endpoint directories & files


/DATASETUP       : ASCII files
input data file for sunfluidh : input3d.dat

/GRID            : ASCII files
input data file         : data_meshgen.d
grid files for sunfluidh: maillx.d, mailly.d, maillz.d

/SNAPSHOTS       : snapshots binary files res_xxxxx_yyyyyyy.d

/TIMESERIES      : ASCII files
u_ins_00000.d , v_ins_00000.d and p_ins_00000.d (timeseries of the velocity components and pressure from probe) 