# Influence of Baffle Location on the Diodicity of Tesla Valves
## 1 Introduction  
The Tesla valve (TV), invented by the well-known inventor and engineer [PERSON], has a unique design with an asymmetrical structure [1], which not only simplifies the valve's construction but also enhances its reliability and durability across a myriad of industrial applications [2, 3]. TVs are widely used in thermal manipulation fluidics [4, 5, 6], micromixers [7, 8, 9], and micropumps [10, 11]. Building upon previous research, this study has significantly enhanced the diodicity of single-stage Tesla valves by introducing baffle designs. Through a detailed analysis of the impact of baffle placement on the flow field, specific optimization recommendations have been proposed. Compared with the research by [PERSON] et al. [12], this study not only focuses on the effects of channel dimensions and fluid properties but also achieves remarkable performance improvements through geometric optimization. In contrast to the work by [PERSON] et al. [13], this study places greater emphasis on enhancing diodicity via geometric optimization rather than relying on complex microfluidic techniques. When compared with the study by [PERSON] et al. [14], this research further optimizes the non-uniformity of the flow field by incorporating baffle designs, thereby achieving higher diodicity. These findings offer new insights and methodologies for the advancement ofmicrofluidic technologies. Reference [15] defines the diodicity as follows: the ratio of pressure drop during reverse flow to pressure drop during forward flow. The formula is as follows:  
\[\text{Di}=\left(\Delta P_{r}\right)/\left(\Delta P_{f}\right) \tag{1}\]  
Studies have shown that the design parameters and structural layout of single-stage TV have a significant impact on its diodicity [16; 17]. Research indicates that reducing flow channel angles significantly impacts valve performance. Smaller angles increase resistance to reverse flow, thereby enhancing valve diodicity. Increasing inlet flow velocities is another parameter that can refine diodicity [18; 19; 20]. Higher velocities lead to a more substantial pressure differential across the valve, subsequently bolstering its diodicity [21; 22]. The aspect ratio, defined as the ratio of the width to the height of the flow channel section, plays a crucial role in fluid dynamics. An increased aspect ratio promotes streamlined flow, reducing turbulence and enhancing the valve's diodicity [23; 24; 25]. Shortening the lengths of straight flow channels also improves diodicity. By reducing the length, the valve can more effectively resist reverse flow, as there is less distance for fluid to accumulate momentum in the reverse direction [26; 27; 28; 29]. For TVs operating at low Reynolds numbers, optimizing the width of the flow channel section is crucial. An optimally adjusted width facilitates more controlled flow, enhancing valve performance by reducing resistance to forward flow and increasing resistance to reverse flow [30]. Some researchers have employed topological optimization techniques to further refine the diodicity [31]. Although there is a wealth of literature on the structural optimization design of single-stage TVs, most of it remains at the level of adjusting geometric parameters, without delving into optimization based on the inherent characteristics. Our previous research has shown that increasing the number of stages significantly enhances the performance of multi-stage TVs, primarily due to the inherent characteristics of the TV that lead to non-uniformity in the flow field [32; 33]. Therefore, we propose the incorporation of baffles into the TV design. We fabricated the TVs with baffles using 3D printing technology for the experiment, while simultaneously developing a simulation model to analyze their diodicity. Such a modification introduces non-uniformity into the flow field, which subsequently modulates the valve's diodicity.