Abstract: Shallow lakes in China are commonly characterized by broad water surfaces, unstable flow pathways, and weak hydrodynamic conditions. Under the combined influence of human activities and climate change, many shallow lakes face insufficient pollutant dispersion and water-quality deterioration. Improving hydrodynamic circulation is therefore essential for enhancing water renewal and ecological restoration. However, configuring artificial circulation devices remains challenging due to complex lake geometries and spatially heterogeneous flow conditions. This study developed a two-dimensional hydrodynamic and water-exchange model for Xinglin Bay, a typical shallow enclosed lake in Xiamen, China, and proposed a kinetic-energy-based point-source layout method for water-purification devices. The method considers lake boundaries, island distribution, and circulation connectivity to determine optimal intake and discharge locations. Single-device and multi-device operation scenarios were simulated to investigate circulation evolution, water-exchange efficiency, and synergistic effects among multiple devices. The single-device simulations showed that device layout strongly controls the spatial distribution of induced circulation and water exchange. Intake points are better suited to relatively open waters, while intake and discharge points of the same device should be positioned close together to establish stable circulation. For adjacent devices, the discharge pathway of one device should connect with the intake pathway of the next device to form continuous circulation. Devices located in narrow island channels generated stable channel-following or around-island circulation, effectively improving water exchange in island areas, whereas devices in the open main lake area mainly enhanced nearshore circulation and improved weak-exchange zones. These results indicate that lake morphology provides important constraints on artificial circulation development and determines the spatial pattern of water exchange. The water-exchange process under single-device operation exhibited clear temporal variations. During the first 0–30 days, circulation cells gradually developed, and more than 60% of the affected areas underwent water exchange, although the exchange efficiency remained relatively low. From days 30 to 60, circulation pathways expanded and stabilized, and the water-exchange rate within affected areas increased to approximately 60%–80%. The results demonstrate that operating duration is a key factor controlling water renewal efficiency. Meanwhile, narrow island channels promoted stronger and more uniform circulation, whereas circulation in the broad main lake developed initially along shorelines and gradually extended toward the central region. Multi-device operation revealed a transition from independent local circulation to synergistic lake-wide circulation. During the initial stage, each device mainly maintained its own circulation system, and the exchange characteristics were similar to those under individual operation. With prolonged operation, interactions among different circulation systems generated secondary circulation in previously low-flow areas. A large-scale circulation pattern was established, and the newly formed secondary circulation significantly enhanced water exchange in central lake areas and island transition zones. Compared with individual-device operation, the water-exchange rate in these newly affected areas increased from nearly 0 to approximately 80%. Quantitative analysis further confirmed the synergistic benefits of multi-device operation. Compared with the linear superposition of individual devices, the proportion of lake area with flow velocity greater than 0.2 m/s increased from 20% to 26%, while the proportion with velocity greater than 0.1 m/s increased from 69% to 78%. After 60 days of operation, the average lake-wide water-exchange rate increased from 61% under independent device operation to 70% under combined operation. These results demonstrate that multi-device operation does not simply represent a linear combination of individual circulation patterns; instead, interactions among induced flows generate secondary circulation and improve both hydrodynamic activity and spatial coverage. This study highlights that effective hydrodynamic restoration of shallow enclosed lakes depends not only on device capacity but also on the spatial organization and connectivity of induced circulation pathways. The proposed point-source layout method provides a practical strategy for transforming isolated artificial disturbances into continuous lake-scale circulation networks and offers new insights for improving water exchange and ecological restoration in enclosed or weakly flushed shallow lakes.