Mishna Niddah 5, 6:
פרק ה - משנה ו
גַּל שֶׁנִּתְלַשׁ וּבוֹ אַרְבָּעִים סְאָה, וְנָפַל עַל הָאָדָם וְעַל הַכֵּלִים, טְהוֹרִים.
If a wave containing forty se'ah [of water] was detached [from the sea] and fell upon a man or upon vessels [that were unclean], they are now clean.
ברטנורא = לְחֻלִּין בִּלְבַד, דְּחֻלִּין לֹא בָעוּ כַוָּנָה. אֲבָל לְמַעֲשֵׂר שֵׁנִי וְלִתְרוּמָה, לֹא טָהַר הַטּוֹבֵל עַד שֶׁיְּכַוֵּן:
Bartenura = For Chulin only, because Chulin don't need cavana , (the fact that they was immersed is good enough.) but for Maasser Sheni and Teruma, one who immerses is not clean until he has a special intent to be clean.
object should be dunked?
--> Yes
For Tevila the only problems concerning action and intention are derabanan and are not relevant for tevila lachulin. See Mishna Chagiga 2, 6(1). For ykar hadin נתלש הגל is good. There is no passive than to receive a wave.
(1)
פרק ב - משנה ו
הַטּוֹבֵל לְחֻלִּין וְהֻחְזַק לְחֻלִּין, אָסוּר לְמַעֲשֵׂר. טָבַל לְמַעֲשֵׂר וְהֻחְזַק לְמַעֲשֵׂר, אָסוּר לִתְרוּמָה. טָבַל לִתְרוּמָה, וְהֻחְזַק לִתְרוּמָה, אָסוּר לְקֹדֶשׁ. טָבַל לְקֹדֶשׁ וְהֻחְזַק לְקֹדֶשׁ, אָסוּר לְחַטָּאת. טָבַל לְחָמוּר, מֻתָּר לְקַל. טָבַל וְלֹא הֻחְזַק, כְּאִלּוּ לֹא טָבָל {י}:
This Mishna shows cavanot for Tevila for Maasser, Teruma, Kodesh, Chat'at. The necessary intent to immerse e. g. for kodesh in way to be considered able to deal with Kodesh is derabanan. But for Chulin those special stringencies don't exist.