Main aspects of the space–time computational FSI techniques and examples of challenging problems solved

Abstract

Flow problems with moving boundaries and interfaces include fluid-structure interaction (FSI) and a number of other classes of problems, have an important place in engineering analysis and design, and offer some formidable computational challenges. Bringing solution and analysis to such flow problems motivated the development of the Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) method. Since its inception, the DSD/SST method and its improved versions have been applied to a diverse set of challenging problems with a common core computational technology need. The classes of problems solved include free-surface and two-fluid flows, fluid-object and fluid-particle interaction, FSI, and flows with solid surfaces in fast, linear or rotational relative motion. Some of the most challenging FSI problems, including parachute FSI and arterial FSI, are being solved and analyzed with the DSD/SST method as a core technology. Better accuracy and improved turbulence modeling were brought with the recently-introduced variational multiscale (VMS) version of the DSD/SST method, which is called DSD/SST-VMST (also ST-VMS). In specific classes of problems, such as parachute FSI, arterial FSI, aerodynamics of flapping wings, and wind-turbine aerodynamics, the scope and accuracy of the FSI modeling were increased with the special ST FSI techniques targeting each of those classes of problems. This article provides an overview of the core ST FSI technique, its recent versions, and the special ST FSI techniques. It also provides examples of challenging problems solved and analyzed in parachute FSI, arterial FSI, aerodynamics of flapping wings, and wind-turbine aerodynamics.

Computational Flow Analysis in Aerospace, Energy and Transportation Technologies with the Variational Multiscale Methods

“…Multi-Domain Method (MDM) [31], and the ST-C data compression method [32]. The special methods used in combination with the ALE-VMS include weak enforcement of no-slip boundary conditions [3335] and sliding interfaces [36,37] (the acronym SI will also indicate that).…”

“…The ST-C [32], which serves here as a data com- tation and store all that data. This version was named ST-C-SPT in [32].…”

“…The ST-C [32], which serves here as a data com- tation and store all that data. This version was named ST-C-SPT in [32]. The ST-C, as a data compression method, was used in a number computations (see [6,8,76, 8385]), with applications ranging from multiscale thermo-uid analysis of a ground vehicle and its tires to thermo-uid analysis of a disk brake, to ow-driven string dynamics in turbomachinery.…”

“…For more on the ST-C, see [32]. In the ow analyses presented here, the ST-C-SPT is used in the thermo-uid analysis of a freight truck and its rear set of tires.…”

Phase transformation and heat conduction interaction analysis and sensitivity analysis to temperature in quenching process of steel considering variability in its chemical composition

“…のほかに，オーステナイト相，フェライト相，ベイナイト相がある (Porter et al, 2009) ．部品内部を靭性の高い ベイナイト相， 表面を耐摩耗性の高いマルテンサイト相に変態させることで部品の機械特性を制御する． しかし， 熱ひずみや変態ひずみのため，焼入れ後に変形を修正する後加工が必要となり，製造コストがかかる．しかも， 変形には大きなばらつきがあり，特段の規則性が見いだせず，ばらつきの制御は困難な状況にある． 有限要素法による鋼材焼入れプロセスシミュレーションでは，炭素拡散，相変態，熱伝導，熱変形を考える連 成問題を解く必要がある (Denga andJuc, 2013, Liscic et al, 2010) ．井上ら (Inoue et al, 1981)は以前よりこの問題 に取組み，解析手法ならびに日本刀も含めた数多くの解析事例を示してきた．Miao ら (Miao et al, 2018)は熱変 形抑制のプロセスパラメータの決定にシミュレーションを活用した．また，アルミ合金に対する熱処理シミュレ ーションの報告もある (Güzel et al, 2009)． ほかにも連成シミュレーションの研究は盛んに行われ，流体構造連 成問題 (Ishihara and Horie, 2014, Mitsume et al, 2014, Mola et al, 2011, Takizawa and Tezduyar, 2014のほか，MEMS の静電気-構造の問題 (Martowicz et al, 2011)や圧電解析 (Asai et al, 2007)などの研究がある．連成解析は材料 加工プロセスシミュレーション (Bergheau, 2014, Radi andEl Hami, 2016)には必須であり，溶接シミュレーション (Goldak andAkhlaghi, 2010, Lindgren, 2007) (Guo et al, 2005(Guo et al, , 2013 The differences among 18 cases were seen after 12.6s. Table 2.…”