One-way coupled simulation of FIV in a 7-pin wire-wrapped fuel pin bundle

A multi-stage approach of simulating turbulence-induced vibrations in a wire-wrapped tube bundle for fretting wear prediction

“…This is exploited for plotting, by averaging the force data over the 6 slabs after applying the appropriate rotation. Also for calculating the Power Spectral Density (PSD) advantage is taken of this, by averaging the PSDs corresponding to each 1/6 th pitch, thereby improving the statistical convergence [18]. The resulting forces on the central pin as a function of height are shown in Figure 9.…”

“…When turbulence-induced vibrations are investigated in literature, the excitation load is often modeled as band-limited Gaussian white noise, obtained by applying the inverse Fourier transform to a (semi-)empirical spectrum [44,45,51,55,56,65] or one resulting from simulations [18,24]. If forces are generated at multiple locations they are often assumed to be either uncorrelated [24,66] or completely correlated [51,65].…”

“…This technique of synthesizing force data from LES results was demonstrated in the work of Brockmeyer [18], but for the sake of completeness it is explained below. It is worth mentioning that the generated force histories in this work are limited to a bandwidth of 10-4000 Hz.…”

“…When turbulence is of concern, large-eddy simulations (LES) or direct numerical simulations are more sound, as in (U)RANS the turbulence is modeled rather than resolved, meaning that only the effect on the main flow is captured well. Examples of LES in a wirewrapped bundle includes the work of Fischer et al [15], Merzari et al [11,16] and Brockmeyer et al [12,17,18]. The downside of large-eddy simulations is the higher computational cost, especially at an elevated Reynolds number.…”

“…When the turbulent, fluctuating pressure field is obtained through LES, it can be used as the excitation in a one-way coupled FSI simulation to obtain the displacement response. This has been done in earlier work to assess FIV in PWR [22][23][24] and LMFR [18]. It is assumed that feedback from structural displacement on the flow is negligible, as the displacements in TIV are usually rather small.…”